Yamaha DTXpress/DTXplorer/DTXtreme

hi i'm trying to pilot the reason's redrum by playing the dtx but i 
only have three midi lines working when i hit the other pads nothing 
happens in the redrum the sounds stay silent for all the other pads !! 
whats strange is that when i connect to the synth all the dtx pads 
play the sounds !! so why don't they play the redrum if anyone could 
help me out that would be great !!!!
thanx