1. Please get jboss 3 rc2 (or 3.1 from cvs if you are feeling adventurous)
2. Get the firebird-service.xml from docs/examples/jca as a starting point. (It is an xa compliant jca adapter, not using a wrapper)
3. Starting up with your rar in the deploy dir you should get a jboss.jca:service=RARDeployment,name=<display name of your adapter> mbean showing on port 8082. If not, I'd suspect a problem in your packaging or ra.xml. Some error should be reported.
4. Set the OldRarDeployment attribute in your *-service to the object name of what you found in (3).
5. Set the ManagedConnectionFactoryProperties appropriately. You can use the format in ra.xml or a condensed format (I think I converted the firebird example, if not look at another one)
6. Set up the security following the instructions in the example file.
There's a lot of explanation of each attribute in the generated jmx-api documentation under docs.