Portability and Interoperability Testing

BPEL implementors:

    I've been giving some thought lately to the issues of testing or 
demonstrating compliance to the WS-BPEL specification. As we have 
discussed in the past this really falls into two categories: portability 
and interoperability.

    Historically there have been several approaches to testing such 
compliance. Our situation is complicated by dependencies on 
implementation-specific messaging infrastructure, so we have some other 
issues to deal with before we get to the main event. What approaches do 
you, the implementors of BPEL, see as the most likely to demonstrate 
BPEL compliance, portability, and (reasonable) interoperability? Should 
we start trying to spin up an effort (perhaps external) to do this?

    I believe that doing nothing in this domain will do a lot of harm to 
BPEL. Are we at the right stage in BPEL's life to worry about this? Or 
has someone started addressing this issue already?

Cheers,
-Ron