In order to use the last resource gambit what do I have to do?
Do I order my calls so that the last call is made to the non-xa resource or
is there a configuration file in jboss transactions I need to modify?
There's a section in the ArjunaCore manual concerning this. It's to do with generic 2PC participants. Unfortunately due to some contract issues, the JTA support was removed when JBoss acquired JBossTS last year and we haven't added it back yet.