How do I assign a Razer DeathAdder Black Edition key to Mission Control?
I've got my Razer Naga configured to work with Mission Control.

I've used the Razer drivers to set up the button I want to use to trigger Mission Control to trigger Mouse Button 3 (you can bind any button to this):


Then, I've set up System Preferences to use Mouse Button 3 to trigger Mission Control:


That's been working fine for me; no extra software required.