Starting JBoss AS6, the server ships with HornetQ as the messaging implementation http://www.jboss.org/hornetq. HornetQ does not use a relational database for persistence. Instead it uses its own file system based journal http://hornetq.sourceforge.net/docs/hornetq-2.1.2.Final/user-manual/en/html/persistence.html. As such, you won't find those *-jdbc*-service.xml in AS6.
The document is correct, but for a complete different implementation.
With JBoss6 you will have hornetMQ (jboss5 it is JBossMessaging and until 4.2 it is JBossMQ).
hornetMQ will run complete without database.
Look into the documentation of hornetMQ (I'm not really familar with it ATM)
hope it helps
Thanks for your help! I think the document need to be updated.