Message

If the VAT total amount in an invoice exists it MUST contain the suppliers VAT number.

Context
ubl:Invoice
Test
((cac:TaxTotal[cac:TaxSubtotal/cac:TaxCategory/cac:TaxScheme/cbc:ID = 'VAT']/cbc:TaxAmount != 0) and (cac:AccountingSupplierParty/cac:Party/cac:PartyTaxScheme/cbc:CompanyID) or (cac:TaxTotal[cac:TaxSubtotal/cac:TaxCategory/cac:TaxScheme/cbc:ID = 'VAT']/cbc:TaxAmount = 0) or not((cac:TaxTotal[cac:TaxSubtotal/cac:TaxCategory/cac:TaxScheme/cbc:ID = 'VAT'])))
Usage
/ ubl:Invoice / cac:AccountingSupplierParty / cac:Party / cac:PartyTaxScheme / cbc:CompanyID
/ ubl:Invoice / cac:AccountingSupplierParty / cac:Party / cac:PartyTaxScheme / cac:TaxScheme / cbc:ID
/ ubl:Invoice / cac:AccountingCustomerParty / cac:Party / cac:PartyTaxScheme / cac:TaxScheme / cbc:ID