Message

In order for the buyer to automatically identify a supplier, the Seller identifier (BT-29), the Seller legal registration identifier (BT-30) and/or the Seller VAT identifier (BT-31) shall be present. 

Context
cac:AccountingSupplierParty
Test
exists(cac:Party/cac:PartyTaxScheme[cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']/cbc:CompanyID) or exists(cac:Party/cac:PartyIdentification/cbc:ID) or exists(cac:Party/cac:PartyLegalEntity/cbc:CompanyID)
Usage
/ ubl:Invoice / cac:AccountingSupplierParty / cac:Party / cac:PartyIdentification / cbc:ID
/ ubl:Invoice / cac:AccountingSupplierParty / cac:Party / cac:PartyTaxScheme / cbc:CompanyID
/ ubl:Invoice / cac:AccountingSupplierParty / cac:Party / cac:PartyLegalEntity / cbc:CompanyID
/ ubl:CreditNote / cac:AccountingSupplierParty / cac:Party / cac:PartyIdentification / cbc:ID
/ ubl:CreditNote / cac:AccountingSupplierParty / cac:Party / cac:PartyTaxScheme / cbc:CompanyID
/ ubl:CreditNote / cac:AccountingSupplierParty / cac:Party / cac:PartyLegalEntity / cbc:CompanyID