Age of Empires III + gaming mouse?

[Naki]

I have a MS SideWinder X8 gaming mouse.

It has the following extra buttons:
Mouse Wheel Left Tilt
Mouse Wheel Right Tilt
Forward
Back

I want to use these extra buttons in RTS games I play, like WarCraft III, Age of Empires III, Command and Conquer 3, StarCraft II, Command and Conquer: Red Alert 3.
Any suggestions what to set those buttons to do in these five games? I think I need to set them to a specific keyboard key/combo.

[Angelspit]

I never saw any point in using the extra buttons of gaming keyboards and mice, I just disable them. It takes quite a while to get yourself to use them effectively, and it's easy to accidentally press those buttons at the wrong time.

But you might get a more useful answer if you find a forum dedicated to those games.