This video, via rolandmedia, is a quick demo of using the Roland TR-8 live as a sound module.
Nate Morton, drummer for The Voice, demonstrates how he uses a Roland TR-8 Rhythm Performer as a sound module with a TD-15KV V-Drums kit.
Why use the TR-8, vs the built-in sounds?
According to Roland, “direct sound control and the sound detail of ACB may play a factor. If the music director wants more low end on the kick or a snappier snare sound, Nate has full control from the surface knobs and sliders, unlike the TD-15 sound module.”
Additional details on the setup are available at Roland’s site.