There is currently no complete, validated solution for transaction bridging. However, a prototype XTS to JTA bridge was developed for JavaOne 2007. You can check it out from the JBossTS anonymous svn repository workspace area:
Thank you very much. The example works perfectly.
I'm glad to hear you got it to work. If you would be interested in exteningd it to do JTA to XTS bridging I'd be even happier :-)