Yamaha DTXpress/DTXplorer/DTXtreme

Hi to all,

 I've notice that when I hit the hi-hat or the tom3 near to rack 
connection point the hi-hat produce sound from snare and tom3 voice 
from ride. I tried different trigger type but the problem was worst. 
STD Med is what I always used.
Why is that happening?
To help you understand the exact area that the wrong voice produces 
see the following pic

http://www.athprobe.com/pic.jpg

thanks in advance 
Antonis