My, you like to do things the hard way, don't you? When JBoss AS deploys the *-ds.xml file, it generates a number of MBeans based on the *-ds.xml contents. So the trick would be to generate those MBeans programmatically.
It would actually be easier to programmatically generate the *-ds.xml file (in some temp directory), and then programmatically move the file into the deploy directory. (I know this was discussed a time or two before but I cannot those posts...)