I'm also interested in this topic. So far I can warn about the Sun One Studio naming conventions when creating getter setter methods. E.g. when your Database Column contains underscores like in NO_PURCHASES Sun is creating getNoPurchases from it.
In my case I already have the relational datamodel, and use a plsql package to generate the ejb.jar and jbosscmp-jdbc.xml templates. And there I do not convert the columnn names.