as far as i can tell... making ENTER your dnp override hotkey will work by default. just don't put it on your DNP list (this might be the issue)

i was able to test here @ work. 2 keyclones... WASD on dnp.. ENTER as dnp override hotkey... 1 notepad each.. connected.

typing 'warcraft' only sent 'rcrft' to the clone.. hitting ENTER then typing 'warcraft' gave me 'warcraft' on clone

also, make sure you are running v1.8f