I remember the urn issue being discussed in the Registry TC.
As Chris pointed out, it is useful for unresolvable URIs.
I am not an expert on the topic - but couple of thoughts
for whatever they are worth;
1. RFC 3121 (http://www.faqs.org/rfcs/rfc3121.html) has the urn
definitions
for OASIS. We need to follow these conventions. According to RFC
3121,
"Validation mechanism:
None specified. The owner will publish OASIS TR9401 Catalogs.
The presence of a URN in a catalog indicates that it is valid."
2. The ebXML JC might be the right forum to do the co-ordination?
Regards,
-Suresh