Customize Change Spaces Shortcut in Mountain Lion I have a Logitech mouse that is supposedly "unsupported", but I'd like to be able to click the mouse wheel left and right to switch spaces left and right. I figured out that Mountain Lion is interpreting these clicks as control + page up (click mouse wheel left) and control + page down (click mouse wheel right), because my IDE (Eclipse) switches text editor tabs when I click left and right. (See https://stackoverflow.com/a/2332440).

How can I map control + page up / control + page down to change spaces left and right? 

There isn't a clear way to do this in System Preferences. I'm comfortable doing some defaults writes from Terminal, but I don't know where to start.
Have you tried BetterTouchTool to achieve it?