While playing around with the this CMP example from the doc, I found out that removing the jbosscmp-jdbc.xml from the jar-file does not produce any errors at deployment. Also the tests run fine.
That makes me belive, that the information contained in jbosscmp-jdbc.xml only has "cosmetic" nature, such as renaming table names. I understand that I can overwrite the default DS and the mapping here.
But why should I have a "redundant" section here. The relations are already defined in ejb-jar.xml
As said before the application works without the mentioned file.