Have any of you BFD'ers (my computer-printed receipt actually said "Big Friggin' Drums" on it

) figured out how to use the variable hi-hat sample key? I tried mapping it to the mod wheel of my keyboard and it didn't work properly: there were dead spots everywhere except top, middle and bottom of the wheel. I also tried it with the sustain pedal with even weirder results. Can't find anything in the manual about it...