I would export an entry from FGU and then open up the module it creates (you can open .mod with winrar or w/e) If you look into that, you'll see how FGU uses xml.
Alternatively, you could look inside a campaign's db.xml, which will show all of the entries (story, npc, ect) and use that.
If I remember right, Oggdude's uses .xml as well, so there's definitely a possibility there. I ran some regex at some point in JS that more or less made everything from oggdudes work in FGU.

