Yamaha DTXpress/DTXplorer/DTXtreme

I know its a sin to mention roland drum gear in this group, but I'm 
going to do it (it'll be brief).  I plugged my spd-6 into the 
dtxpress via a midi cable, I think I'm getting the dtx's sounds.  
Does anyone know how to change the sounds I'm getting on the spd-6 
from the dtxpress?  And one more question, does anyone know of any 
place I could go on the net (group like this one or website) to get 
more info on the spd-6.  Any info is appreciated, thanks.  -Joe