diff --git a/src/XmlConverterCiiToUbl.php b/src/XmlConverterCiiToUbl.php
index 98c786a..8f01690 100644
--- a/src/XmlConverterCiiToUbl.php
+++ b/src/XmlConverterCiiToUbl.php
@@ -409,6 +409,11 @@ function ($sellerTradePartyUniversalCommNode) {
                     }
                 );
 
+                // Set the IDs of the seller
+                // ID's cardinallity
+                // CII - ID is 0..unbounded, GlobalID is 0..unbounded
+                // UBL - PartyIdentification is 0..unbounded
+
                 $this->source->queryAll('./ram:ID', $sellerTradePartyNode)->forEach(
                     function ($sellerTradePartyIdNode) {
                         $this->destination->startElement('cac:PartyIdentification');
@@ -430,9 +435,7 @@ function ($sellerTradePartyGlobalIdNode) {
                     $invoiceHeaderSettlement,
                     function ($DirectDebitMandateNode) {
                         $this->destination->startElement('cac:PartyIdentification');
-                        $this->destination->startElement('cbc:ID', $DirectDebitMandateNode->nodeValue);
-                        $this->destination->attribute('schemeID', 'SEPA');
-                        $this->destination->endElement();
+                        $this->destination->elementWithAttribute('cbc:ID', $DirectDebitMandateNode->nodeValue, 'schemeID', 'SEPA');
                         $this->destination->endElement();
                     }
                 );
@@ -559,6 +562,11 @@ function ($buyerTradePartyUniversalCommNode) {
                     }
                 );
 
+                // Set the IDs of the buyer
+                // ID's cardinallity
+                // CII - ID is 0..1, GlobalID is 0..1
+                // UBL - PartyIdentification is 0..1
+
                 $this->source->whenExists(
                     './ram:GlobalID',
                     $buyerTradePartyNode,
@@ -702,6 +710,11 @@ function ($payeeTradePartyUniversalCommNode) {
                     }
                 );
 
+                // Set the IDs of the payee
+                // ID's cardinallity
+                // CII - ID is 0..1, GlobalID is 0..1
+                // UBL - PartyIdentification is 0..1
+
                 $this->source->whenExists(
                     './ram:GlobalID',
                     $payeeTradePartyNode,
@@ -835,16 +848,6 @@ private function convertTaxRepresentativeParty(): void
             function ($sellerTaxRepresentativePartyNode) {
                 $this->destination->startElement('cac:TaxRepresentativeParty');
 
-                $this->source->whenExists(
-                    './ram:URIUniversalCommunication/ram:URIID',
-                    $sellerTaxRepresentativePartyNode,
-                    function ($sellerTaxRepresentativePartyUniversalCommNode) {
-                        $this->destination->startElement('cbc:EndpointID', $sellerTaxRepresentativePartyUniversalCommNode->nodeValue);
-                        $this->destination->attribute('schemeID', $this->source->queryValue('./@schemeID', $sellerTaxRepresentativePartyUniversalCommNode));
-                        $this->destination->endElement();
-                    }
-                );
-
                 $this->source->whenExists(
                     './ram:Name',
                     $sellerTaxRepresentativePartyNode,
@@ -945,6 +948,11 @@ function ($shipToTradePartyNode) use ($invoiceHeaderDelivery) {
 
                 $this->destination->startElement('cac:DeliveryLocation');
 
+                // Set the IDs of the ship to party
+                // ID's cardinallity
+                // CII - ID is 0..1, GlobalID is 0..1
+                // UBL - PartyIdentification is 0..1
+
                 $this->source->whenExists(
                     './ram:GlobalID',
                     $shipToTradePartyNode,
diff --git a/src/XmlConverterUblToCii.php b/src/XmlConverterUblToCii.php
index f0d04ff..f3da38b 100644
--- a/src/XmlConverterUblToCii.php
+++ b/src/XmlConverterUblToCii.php
@@ -385,16 +385,24 @@ private function convertApplicableHeaderTradeAgreement(): void
             $docRootElement,
             function ($invoiceAccountingSupplierPartyNode) {
                 $this->destination->startElement('ram:SellerTradeParty');
+
+                // Set the IDs of the seller
+                // ID's cardinallity
+                // UBL - PartyIdentification is 0..unbounded
+                // CII - ID is 0..unbounded, GlobalID is 0..unbounded
+
                 $this->source->queryAll('./cac:PartyIdentification/cbc:ID[not(@schemeID)]', $invoiceAccountingSupplierPartyNode)->forEach(
                     function ($invoiceAccountingSupplierPartyIdNode) {
                         $this->destination->element('ram:ID', $invoiceAccountingSupplierPartyIdNode->nodeValue);
                     }
                 );
+
                 $this->source->queryAll('./cac:PartyIdentification/cbc:ID[@schemeID != \'\' and @schemeID != \'SEPA\']', $invoiceAccountingSupplierPartyNode)->forEach(
                     function ($invoiceAccountingSupplierPartyIdNode) {
                         $this->destination->elementWithAttribute('ram:GlobalID', $invoiceAccountingSupplierPartyIdNode->nodeValue, 'schemeID', $invoiceAccountingSupplierPartyIdNode->getAttribute('schemeID'));
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:PartyLegalEntity/cbc:RegistrationName',
                     $invoiceAccountingSupplierPartyNode,
@@ -402,6 +410,7 @@ function ($invoiceAccountingSupplierPartyNodeRegNameNode) {
                         $this->destination->element('ram:Name', $invoiceAccountingSupplierPartyNodeRegNameNode->nodeValue);
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:PartyLegalEntity/cbc:CompanyLegalForm',
                     $invoiceAccountingSupplierPartyNode,
@@ -409,6 +418,7 @@ function ($invoiceAccountingSupplierPartyLegalEntityNode) {
                         $this->destination->element('ram:Description', $invoiceAccountingSupplierPartyLegalEntityNode->nodeValue);
                     }
                 );
+
                 $this->source->whenOneExists(
                     ['./cac:PartyLegalEntity/cbc:CompanyID', './cac:PartyName/cbc:Name'],
                     [$invoiceAccountingSupplierPartyNode, $invoiceAccountingSupplierPartyNode],
@@ -419,6 +429,7 @@ function () use ($invoiceAccountingSupplierPartyNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:Contact',
                     $invoiceAccountingSupplierPartyNode,
@@ -446,6 +457,7 @@ function ($invoiceAccountingSupplierPartyContactMailNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:PostalAddress',
                     $invoiceAccountingSupplierPartyNode,
@@ -460,6 +472,7 @@ function ($invoiceAccountingSupplierPartyPostalAddressNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->source->whenExists(
                     './cbc:EndpointID[@schemeID=\'EM\']',
                     $invoiceAccountingSupplierPartyNode,
@@ -469,6 +482,7 @@ function ($invoiceAccountingSupplierPartyEndpointNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:PartyTaxScheme/cac:TaxScheme/cbc:ID[text() = \'VAT\']',
                     $invoiceAccountingSupplierPartyNode,
@@ -478,6 +492,7 @@ function ($invoiceAccountingSupplierPartyTaxSchemeNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:PartyTaxScheme/cac:TaxScheme/cbc:ID[text() = \'TAX\']',
                     $invoiceAccountingSupplierPartyNode,
@@ -487,6 +502,7 @@ function ($invoiceAccountingSupplierPartyTaxSchemeNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:PartyTaxScheme/cac:TaxScheme/cbc:ID[text() = \'FC\']',
                     $invoiceAccountingSupplierPartyNode,
@@ -496,6 +512,7 @@ function ($invoiceAccountingSupplierPartyTaxSchemeNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->source->whenExists(
                     './cac:PartyTaxScheme/cac:TaxScheme/cbc:ID[text() = \'???\']',
                     $invoiceAccountingSupplierPartyNode,
@@ -505,6 +522,7 @@ function ($invoiceAccountingSupplierPartyTaxSchemeNode) {
                         $this->destination->endElement();
                     }
                 );
+
                 $this->destination->endElement();
             }
         );
@@ -515,6 +533,11 @@ function ($invoiceAccountingSupplierPartyTaxSchemeNode) {
             function ($invoiceAccountingCustomerPartyNode) {
                 $this->destination->startElement('ram:BuyerTradeParty');
 
+                // Set the IDs of the buyer
+                // ID's cardinallity
+                // UBL - PartyIdentification is 0..1
+                // CII - ID is 0..1, GlobalID is 0..1
+
                 $this->source->whenExists(
                     './cac:PartyIdentification/cbc:ID[not(@schemeID)]',
                     $invoiceAccountingCustomerPartyNode,
@@ -809,6 +832,11 @@ private function convertApplicableHeaderTradeDelivery(): void
             function ($deliveryLocationNode, $deliveryNode) {
                 $this->destination->startElement('ram:ShipToTradeParty');
 
+                // Set the IDs of the ship to party
+                // ID's cardinallity
+                // UBL - PartyIdentification is 0..1
+                // CII - ID is 0..1, GlobalID is 0..1
+
                 $this->source->whenExists(
                     './cbc:ID[not(@schemeID)]',
                     $deliveryLocationNode,
@@ -910,6 +938,11 @@ function ($documentCUrrencyNode) {
             function ($invoicePayeePartyNode) {
                 $this->destination->startElement('ram:PayeeTradeParty');
 
+                // Set the IDs of the payee
+                // ID's cardinallity
+                // UBL - PartyIdentification is 0..1
+                // CII - ID is 0..1, GlobalID is 0..1
+
                 $this->source->whenExists(
                     './cac:PartyIdentification/cbc:ID[not(@schemeID)]',
                     $invoicePayeePartyNode,