The XaDataSourceService doesn't set the UserTransactionJndiName, so it defaults to java:/UserTransaction, which seems invalid within the context of AS7.

In-line commit comment here:

https://github.com/jbossas/jboss-as/commit/7fd76db27e89e40e9a16243fc058467d0acc67ae#commitcomment-607839

Additionally, setting up the URL delimeter uses the dataSourceConfig instead of the xaDataSourceConfig, but that seems harmless, so far.

In TorqueBox, we hacked around:

https://github.com/torquebox/torquebox/blob/7f51e360749d8093fc291fbf238b7d2be18ec9a0/modules/core/src/main/java/org/torquebox/core/datasource/HackDataSourceService.java