\_ Has anyone gotten mouse wheels to work on XF86 4+?
Have you tried the docs for XF86 3 and ported them?
http://www.inria.fr/koala/colas/mouse-wheel-scroll/
Simple though, mostly it looks like this (for me in XF86 3.x):
Section "Pointer"
Protocol "IMPS/2"
Device "/dev/mouse"
ZAxisMapping 4 5
EndSection
David