http://www.linuxquestions.org/questi...threadid=71711
The only difference should be that you should use your XF86Config-4 file instead of XF86Config (this seems to be distro specific which file to use, mandrake uses XF86Config-4)
Try this to make sure you are looking for the correct file as well:
less /etc/X11/XF{TAB}
Where {TAB} is pressing the tab key. No spaces and no brackets, just tab. It will autocomplete for you, excellent tool.
Cool