Message

A Party Identifier Scheme MUST be from the list of PEPPOL Party Identifiers described in the "PEPPOL Policy for using Identifiers" followed by a ":".

Context
query:QueryResponse/rim:RegistryObjectList/rim:RegistryObject/rim:Slot[@name='BuyerInformation']/rim:Slot[@name='BuyerPartyIdentification']
Test
rim:SlotValue[@xsi:type='rim:StringValueType']/rim:Value/text()[matches(normalize-space(),'^(0((00[3-9])|(0[1-9]\d)|(1\d{2})|(20\d)|(21[0-3]))):')]
Usage
/ query:QueryResponse / rim:RegistryObjectList / rim:RegistryObject / rim:Slot@name=BuyerInformation / rim:Slot@name=BuyerPartyIdentification / rim:SlotValue / rim:Element / rim:Value