[SLE] Mouse Wheel and SuSE 7.3

I have a Linux Box powered by SuSE Linux 7.3 which works great except for mouse wheel!! I tried Protocol "IMPS/2" in XF86Config-4 but my mouse goes mad :-( why ???? this pc with this mouse (Logitech M-S48a) works fine with Mandrake 8.1 and Xfree 4.1.0.... why not on my SuSE ? help please!! g.