Setting up my controller with Cubase

I never can recall how to do this. I’ve already installed the template for my particular controller in the Generic Devices section of Cubase. However, I want to manually assign Fader 9 (for example) to a specific controller message, in this case, Aftertouch. My controller is an M-Audio Keystation 88 Pro, which does not transmit Aftertouch; however, my Garritan Jazz sample library uses Aftertouch to control Vibrato. The CC for Aftertouch is 131. I have messed with this for an hour, and spent another hour browsing the Web. HELP! :laughing: