A4Tech Wireless mouse wheel not detected

[Justin R. Smith]

FreeBSD jsmith.org 6.0-STABLE FreeBSD 6.0-STABLE #0: Sun Nov 20 15:06:19 
EST 2005     root at jsmith.org:/usr/obj/usr/src/sys/MYKERNEL  i386


I have an A4 Tech wireless keyboard and mouse. Linux and windows both 
find it to be indistinguishable from a PS/2 and use the mouse wheel. The 
Stable FreeBSD doesn't respond to wheel events. sysmouse identifies it 
as a microsoft mouse (with no mouse wheel) but depressing the wheel 
generated middle-button event. Killing sysmoused and configuring the X 
server to access

/dev/psm0

 (with the Zaxismapping, etc) doesn't change anything. I think the 
problem lied in psm0 itself.

Running

xev

show that no X events are generated when turning the mouse wheel.

Any suggestions?