mousewheel controls

[retnuh]

when trying to set controls to my mousewheel, it's as if i haven't done anything it basically cant detect that im scolling up and down, i want to set scroll up to increase my speed and scroll down to decrease. when i push in my mousewheel it recognises it as mousebutton 3. my mousewheel works outside the game as well as in other games. Does anyone know why it doesn't work? i know at least on other person has this prooblem and at least one other person can use the mousewheel. Any advice or input of any kind would be appreciated.