I was looking at doing this project a while back. I ended up with a real yoke and abandoned it, but it's possible if you're willing to do some significant re-engineering. BTW, that "extra" curved bar on the bottom can be removed, or left in place if you don't mind it. Then you'll have to replace the optical encoder on the back with a potentiometer for the right/left motion. That's enough to convert it to regular 270 wheel operation, which is useful for a lot of games all by itself.
The big trick is, of course, adding the forward/back motion. The bar the handles mount to is a welded-on part of the main yoke body, so it'll need to be cut free and then replaced with a new bar, and a bearing system to allow that bar to move. Then, you'll have to find a way to mount a potentiometer, gears and some springs inside that central housing, which is smaller than a standard SW yoke housing.