According to a lot of developers over at xda, the Manila 2.5 is too big and too deep rooted to be placed into a cab file. It needs to be cooked into the rom itself.

The Imagio is still young for a hard spl allowing us to put custom roms on the phone. If you follow the upgrades sections, cmonex is getting to our hspl as soon as she finished work on a project she's working on. At this point, we need to chill out and look forward to the hspl. Just follow along it'll be out soon. Then we'll be cooking roms up with this kick azz features. Trust me it'll be worth the wait!