How do I set my scroll wheel to be mouse button 2 in x11??

[ukdonna]

I have a Kensington pocket mouse that has two buttons and a scroll wheel. For the life of me, I can't seem to set the scroll wheel so that it behaves as mouse button 2 in x11. I have turned off the "emulate 3 button mouse" in x11. I have downloaded mouseworks software from kensington and set the scroll button to be opt - click. But... it doesn't work. When I use 'xev' to see what's happening, x11 still think that the scroll wheel is mouse button one when pressed and mouse buttons 4 and 5 when scrolled up and down. Does anyone have any ideas?

Thanks!
Donna