The ebCore TC is about to release a new specification for public review:  

A mechanism for the identification of business partners in XML business documents and XML message headers based on URN-based identifier types is required in many electronic business exchanges. This specification specifies a formal URN-based mechanism for referencing party types from the ISO 6523, ISO 9735 and ISO 20022 identification scheme catalogs using the oasis URN namespace. Sample applications include (but are not limited to): ebXML message headers; ebXML collaboration protocol profiles and agreements; UBL, UN/CEFACT and OAGIS XML business documents; and the UN/CEFACT SBDH.