[IBR-153-OM] - Buyer identifier (IBT-046) is mandatory with Scheme identifier (IBT-046-1) 'Importer Customs ID' if Invoice transaction type (BTOM-001) is Import of Goods (XXXXXXXXXXXX1XXXXXXX).
IBR-153-OMubl:Invoice | cn:CreditNote not($isImportGoods) or cac:AccountingCustomerParty/cac:Party/cac:PartyIdentification/cbc:ID