Ok this helps... I did know about the transformations of -ds.xml to -service.xml but still was under the impression a basic -service.xml, overridden (where needed) with the generated one. The docs you refer to (and later versions) are what I used. Read them from front to back and reverse, top-left to bottom right and reverse. These are also the docs that mention XATxConnectionManager class, so that is why I still thought it was needed. That confuses a lot, getting refered (not specifically by you, more in general) to use these docs but if the info in it is 'obsolete' (there is a JBoss 5 doc which also still has this chapter) I'll certainly go for the JBoss 5 only solution, but trying the TXConnectionManager first is my quickest win. Thanks again, I'll make sure to blog about this if I get it to work (and I do not see a reason why I wouldn't) View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4270075#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...