I've replaced the jdbc xa wrapper for jboss 4 (cvs HEAD) with an entirely new version that is
--easily extensible to counteract the quirks of vendor drivers.
However, I don't have any XADataSources to find out if it works. If you have an XADataSource based driver, please contribute to jboss by setting up a configuration for it. In jboss 4 this is most easily done with the -ds.xml files.
If you are more ambitious, please write a vendor specific wrapper extending this one that maps our interpretation of the xa spec to the vendor's. You also have an opportunity to more directly specify the XADataSource properties in the wrapper. Ask for more detail if you are interested.
Igor Fedorenko has contributed some xa tests that I am trying to adapt to run inside jboss against jca adapters. This should soon give us a compatibility standard.