This stuff is very hard (at least for me). I tried to wrap a texture around the model in the picture in photoshop, but Warp doesn't give you the ability to add more warp points in CS4. It's also very hard to keep one area from moving without adding more points. I even tried to Liquify it, but Liquify works only in a dialogue box instead of as a tool in later versions. Liquify also wont let you see how the effects turn out if you still have your other layers visible. I really need to upgrade.
I think the best way for me to do this is to draw a grid on a printout around the model to determine how I want to wrap the costume, scan it in, envelope distort the texture in Illustrator, and import it to Photoshop. That should work.