Hi there,
Due tu a customer request, we have made a small patch to the 4.2.3 release in order to allow exceptions from the JDBC driver to be integrated as the cause of XA transaction abortions (in this case, a deferred constraint violation).
I'm not sure if this release is still maintained somehow since I couldn't find a repository for it, but if it is feel free to have a look at the attached patch file and integrate it if needed.
Cheers,
Eric