[ibr-tdd-17] – The scheme identifier (TDT-013-1) attribute of cbc:EndpointID (TDT-013) MUST be a Peppol Participant Identifier Scheme.
ibr-tdd-17/pxs:TaxData/pxs:ReportingPartynot(exists(cbc:EndpointID/@schemeID)) or matches(cbc:EndpointID/@schemeID, $regex_pidscheme)