You can definately trap with the wings on. I have this setup. Hobie does not recommend it I don't think. Probably something to do with legal liability as they are worried about the seats collapsing to folded position if you trap off the wings plus it is a little awkward to get hooked up with and trapped out with the wings in place. I've gotten used to it and is no problem now. Just need to get a method down.
Anyway, I just made the adjustment as short as possible since trapping off the wing puts your body at a higher position. No need to shorten the trap wire like you may have read elsewhere. Basically, the black bungee goes through the gromets on either side of the trampoline near the hulls and gets tied to the short white length of rope preferably with a bowline knot. See image below for T handle and dog bone/pulley arrangement. For the mast attachment point, you will notice the mast tang has 3 holes. The lowest hole is used for the jib stay and shrouds. Used an appropriate sized shackle (I don't have a picture, but can get one later today if needed) and both holes in the upper part of the mast tang for the trap wires. Thread the U shaped part of the shackle through the center hole of the mast tang, open end up, then hook your trap wire to either side of the shackle and pin the shackle through the upper most hole in the tang. Not as complicated as it sounds.
Good luck - it's tons of fun.