A sellers financial institution identifier MUST be provided if the scheme of the account identifier is IBAN and the payment means is international bank transfer
//cac:PaymentMeans(cac:PayeeFinancialAccount/cbc:ID/@schemeID and (cac:PayeeFinancialAccount/cbc:ID/@schemeID = 'IBAN') and cac:PayeeFinancialAccount/cac:FinancialInstitutionBranch/cac:FinancialInstitution/cbc:ID) or (cac:PayeeFinancialAccount/cbc:ID/@schemeID != 'IBAN') or (not(cac:PayeeFinancialAccount/cbc:ID/@schemeID))