I don't mean to be harsh, but this might not be the best forum to get help on xbox mods. It is, after all, "Build your own arcade cabinet". There's lots of xbox modder sites out there that might be more help.
Personally, I don't even own an xbox, so I couldn't help with the problem anyway, though, I will say that some of your terminology doesn't seem quite right. For instance...
FBA has the game rom files as ini. Mame, has them as zip files
If those are the INI files I'm thinking of (typical of pc's), they're just text files and can't possibly contain rom images. They MIGHT be INI files used to describe parameters about some +other+ files that ARE rom images, but that's just a guess.
Mame packages the rom images, as well as other necessary components for a game, into a ZIP file so that it's much easier to deal with. Open one of those zip files up and you'll see what I mean.
Hope that helps, or at least points you in a good direction.