TPA reference element?

Another issue for next month's kickoff--
probably under the small additions category--
is to add an optional element that can reference a TPA
that is to be associated with a CPA. 

Just as we now have pointers off to trading
partner information, and business process specifications, 
a pointer to a TPA might also be useful. 
Some industry groups, RosettaNet for example, 
are exploring specifying TPAs
for their communities in the near future.