Comment 19 for bug 615892

I can confirm this works on a Saitek Cyborg R.A.T.5 Mouse.
Although the xinput tool had no effect, putting this in the xorg.conf did had effect.

I did the following on Ubuntu 10.10:
create a /etc/xorg.conf file with:
Section "InputClass"
        Identifier "Mouse Remap"
        MatchProduct "Saitek Cyborg R.A.T.5 Mouse"
        MatchDevicePath "/dev/input/event*"
        Option "ButtonMapping" "1 2 3 4 5 6 7 2 9 10 11 12 0 0 0 16 17 18 19 20 21"
EndSection
Restart X or reboot.