Maybe XA is reason why IONA integrates with ActiveBPEL and not with ODE =).
Don't know if ActiveBPEL supports XA, just blind guess. http://www.iona.com/support/docs/artix/orchestration/5.1/orch_relnotes/wwhelp/wwhimpl/common/html/wwhelp.htm?context=release_notes&file=release_notes2.html
