or how about not install the stupid MouseWare at all? I got a dual optical mouseman which has a mouse4 and I did bind it in CS:S...
you can't bind key combinations. If it can be done (like lets say CTRL+1), then it requires to write some weird script which is basically too much hassle and which I still doubt is possible.
the only thing you could do with a script is make it to where ctrl switches back and forth between two sets of keys. for example, if E=use, you could press ctrl, and then E=something else. press ctrl again, and E will be set back to use. i have never seen a way to make to where 2 or more keys in combination do something.
finalcut: i have never heard of anything that allows this and i doubt very seriously you will find something that will do this. even if you do, it probaby wont work in game. i think you should uninstall your mouse drivers and try doing it like that. I have a microsoft intellimouse explorer, and i never install the drivers. mouse1-mouse5 will still bind in game though.