Assign Hotkey to Mouse Button

Hi Guys,

I've been using USB Overdrive to map Mouse button 4 and 5 to to the corresponding hotkeys to switch spaces left and right. It's worked a treat, but I now use SmoothMouse to better fix mouse acceleration issues in OS X, and it strongly recommends to uninstall USB Overdrive and any other such application that hijacks the mouse driver.

I'm hence now looking for an alternate solution to map mouse buttons to hotkeys, or alternatively directly map mouse buttons to switch spaces left and right. It's such a shame Preferences -> Keyboard -> Shortcuts doesn't allow assigning mouse button. It's also frustrating that Preferences -> Mission Control allows mouse button to be assigned to certain actions, space switching not being any of them.

It's incredibly efficient to be able to switch spaces with the forward and back mouse buttons (mouse 4 and mouse 5), for example when moving windows between spaces, it's super quick, and only requires one hand. It's surprising Apple don't provide such a facility out-of-the-box.

So can someone let me know if there's a way to achieve this either without using 3rd party software, or using freeware that doesn't interfere with SmoothMouse? I don't mind if it involves editing plist files, etc.

Cheers,
Tom