How do I reassign the F3 key to another application? I have a gesture for Exposé so I need another button (the F3) to do the same. I'd love to replace F3 to show/hide the MacBartender app. 



Would it be possible to reassign this key for such a use? I have KeyRemap4MacBook installed but it does not allow for changing individual keys (I either change all my function keys or none at all).
FunctionFlip allows you to change the function keys individually.