The Hotkey Remote is what you are looking for. It allows you to use 
key combinations instead of a remote control, but there are some 
limitations due to the way OS X handles emulated keyboard events and 
hotkeys (=> they can overlap and thus the hotkey remote can't be used 
for many but not for every program).

Please give the documentation on the Hotkey Remote a read (=> choose 
"Help" from Remote Buddy's pulldown menu at the top of the screen) for 
more info.

Best regards, 
Felix Schwarz