Its all going to happen in the dd55(or its maybe not going to happen at all). AFAIK, you have to set the midi note number for each pad on the dd55, so each pad with trigger the desired drum sound in the plugin. Alternately, open the plugin and see if you can assign sounds to different midi notes than the default(which is a question for BFD, not Pro Tools).
Here is the page of the dd55 manual that should help you out:
http://i182.photobucket.com/albums/x...2/dd55copy.jpg