[hibernate-dev] Copyright on hibernate XML interface?

Hello, I already posted this question to a hibernate forum but didn't receive any answer. That's why I saw no way round posting to this mailing list. I'm working on a mapping tool that maps Java objects to RFCs. This is somewhat similar to mapping Java objects to relational database tables (though much simpler). I therefore got the idea to use the hibernate hbm.xml mapping syntax for this Java-to-RFC mapping tool, because there is no point in re-inventing the wheel and many many people know hibernate and will therefore quickly feel at home when using this Java-to-RFC mapping tool if it uses the same mapping XML syntax as hibernate. My question is now whether also this hbm.xml mapping syntax is completely free and may be used for another purpose than hibernate itself or whether permission has to be granted by the authors of hibernate. I just want to be really sure before I start, because changing the mapping syntax in the middle of the race is a lot of work. Thanks in advance, Oliver Plohmann