Yamaha DTXpress/DTXplorer/DTXtreme

I have this strange this happening when I try to record a Midi track 
into Cubase, basically only the hi-hat toms and crash cymbal are 
recording, the snare and kick, for some reason are not!  Anyone had 
this before, or have any idea how to remedy?  The triggers are 
definitely working, the module is generating the sounds,, I am not 
sure if it is Cubase or the midi output in the module...

Thanks 

Simon

PS  Cubase is 5.1 and kit is a DTExpress 1.