Done what you have suggested but the next time i rebooted the system, it went in to the command line and could not startx, after
a few minutes thinking what i could do, i just run SaX2 to overwrite what i did to XF86config.
I successfully could get into X and mouse wheel was working
but the side buttons were not
i had another look in the XF86config file and nothing had changed
(the suggested configuration)