Yamaha DTXpress/DTXplorer/DTXtreme

I have been doing my research, and I have decided that the DTXPress 
II is the kit for me.  I will be purchasing it in the next couple of 
weeks when my work bonus comes through.  

My question is this.......I want to add a few additional triggers to 
what is already included with the set.  The triggers I would like to 
add are:

TP80 Single Zone Pad for a 4th Tom
PCY10 Cymbal Bell Pad for ride type sounds or additional crash
BP80 Dual Trigger Bar Pad for additional percussion type things.

Is it possible to add these with the ports that exist?  I looks like 
I would have to double up the toms with stereo splitters, ad the 
cymbal bell pad to the now open tom spot and then connect the Bar to 
9/10.

Is this right?

Am I way off?

HELP!