Yamaha DTXpress/DTXplorer/DTXtreme

I just saw a pict of the  Hart Prosnare innards along with a schematic and understand why it probably won't work on a DTXpress.  Under  
the mesh head is a approx. 6 inch foam cylinder  (1 inch diameter) positioned in the center that transfers  energy to a 10 inch diameter  
aluminum plate.  The piezo is  underneath this plate.  This probably eliminates the hot spot that Roland mesh pads are know for but 
would be WAY too small of a signal for the DTxpress.  
Roland piezo's are 2 inches from the head with a cone shaped foam material transfering energy directly to the piezo.  
According to this schematic the Prosnare has 3 piezos.  One under the aluminum plate and TWO on the shell of the drum.   One of the 
shell  piezo's and the center piezo is wired in parallel. This is a very curious third piezo.  It would seem every time you hit the rim the center 
sound triggers too?!
Jun