JR,
We currently don’t support that direction of generation but will in a future release. Right now the work flow goes:
DB -> XML & Java Source
It is on our TODO list to offer:
XML -> Java Source
generation as well. We also have a Hibernate visual mapper in the works that will allow you to manually build the relationships before generating the XML and Java source, so hopefully most of the manual corrections you need to make in the XML will no logner be needed. The visual mapper was postponed until 5.0 because user demand showed Hibernate 3 support was more important in the existing tool set instead of adding the visual mapper.