Yamaha DTXpress/DTXplorer/DTXtreme

Hi guys, I'm new to the list. First of all, it's a great site. I 
can't beleive my luck finding it when I really need it......

I just started to use my dtxpress with MIDI. I have it hooked up to a 
sequencer and a keyboard. First of all does MIDI merge work the same 
way as MIDI THRU, or do I have to buy a MIDI THRU box. If it is the 
same as THRU, what could be the reason for my sequencer not receiving 
MIDI if it has to go through the DTXpress? IS it even possible to 
have a sequencer play back two different kits on two different MIDI 
channels?

OK, When I play back keyboard tracks from the sequencer, the DTXpress 
tone generator starts to play all kinds of pianos and stuff, 
responding to the notes, it also plays drums sounds. This only 
happens on Channels 1,2,6, 10 & 14 ????. The sequencer only receives 
MIDI on channel 10. To solve the problem temporarily I swapped all my 
channels around to make sure the keyboard wasn't receiving on any of 
those channels.(But this is a waste) I've looked at the mannual as 
much as I can, I just don't seem to be able to find what i'm looking 
for! Can anyone help, any advice would be greatly appreciated. How do 
you set which sounds respond to which channels? Basically, can I set 
it up like this in a "daisy chain" or do I need to use it on its 
own...surely not.

Cheers

Jim