Anyone know how to assign Akai drum pads in Ultrabeat?

I have the Akai MPK mini which has 8 drum pads with 2 banks. I have been trying to assign different drum sounds in Ultrabeat to the pads but have been unable to for some reason. The controller is working w/ ultrabeat when i hit the keys on the keyboard it plays the sounds from the selected drum kit. Also does the same when i hit the pads. But what i cant figure out is how to assign a specific drum sound (note or whatvever) to a specific drum pad on my controller IN ultrabeat itself. Any help w this is much appreciated. Thanks.

-J