As I told you I made some modifications in my XF86Config File
but after a day of use the mouse "lost the right button".
I've found another solution
http://sdb.suse.de/de/sdb/wessels_sax.html#Mausprobleme
if you understand german
Else :
I modified /etc/init.d/boot.local to add this line
/usr/sbin/sysp -s mouse > /dev/null
So that my Imps/2 mouse will be correctly initialised at boot
Then I modified XF86Config file so I obtained the paragraph
as you see it below
Section "InputDevice"
Driver "mouse"
Identifier "Mouse[1]"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "on"
Option "Name" "AutoDetected"
Option "Protocol" "imps/2"
Option "Vendor" "AutoDetected"
Option "ZAxisMapping" "4 5"
Endsection
Note : my mouse is a PS2 mouse (not USB) 2 buttons and wheel
and cordless
It seems that the problem was correctly initialize mouse and then
choose the correct PS2 protocol and eventually correct
management of the wheel
Hope it solves your problem too.
Bye