I have always wondered this myself. I first played KOTOR and TSL on the original Xbox. I'm okay with Mouse & Keyboard, but not as quick as I was before I got the PC versions. With that joy2key thing, is it just for wired/pc versions of the PS3 controller?
Use Xpadder. Free, can set a joystick to operate like the mouse, and you set it up an way you want.
...And I can send some files so you can test it out for ourself with my profile and edit it accordingly.
http://www.xpadder.com/)