Yamaha DTXpress/DTXplorer/DTXtreme

Hey,

Is there any way to turn the velocity sensetivity OFF on a DTXpress 
module?  I'm using NI battery as a smapler and I would like to have 
all samples triggered at the same volume, so i need the DTXpress to 
send the midi velocities all as 127(full volume).  

Anyone have any ideas on how to do this?

Thanks alot,
Dave