If you have a vision, there's no need (or point) in hooking up the additional weight or expense of a separate VTX, and you would invariably run into issues trying to run a 5.8 GHz video system along side the 5.8GHz control signal on the visions.
Simply use the existing system and run HDMI out if your mobile device to a pair of Ziess Cinemizers, or, better yet, use one of the new Epson Moverio BT 200 glasses which don't even require a separate Android decice. There are a lot of topics around here about both of these options, and there are even stickies for the new Movieros. Trying to use Fatsharks on the vision is pretty much redundant and offers no advantages over the aformentiond solutions, even if it would work, which is doubtful because of the frequency conflicts.
