Overriding default behaviors for USB HID 'keyboard' device?

[Paul B. <lin...@sp...>]

  Happy new year, hopefully it finds everyone safe (with only mild
hangovers.. ;-)

  I've recently acquired a Belkin Nostromo n52 "SpeedPad" [1] - a USB gaming
device with a number of keys and a form factor handy for various games. 
It's ostensibly a successor to the Nostromo n50 [2] for which I've helped
cook up some userland utilities [3] to configure the n50 and convert button
hits to user-configurable keystrokes.

  Despite the external similarities the devices are completely different
internally.  The older n50 doesn't even present itself as any specific type
of HID, and so is automatically handled through the generic event interface.
 This is what my userland tools use, and it's worked well enough so far. 

  The newer n52 however presents two interfaces: a USB keyboard and USB
mouse (it has a wheel similar to a mouse wheel, so is a sharply limited
'mouse' device.)  Upon connection, the USB HID subsystem identifies the
n52 properly and sets up its mouse and keyboard interfaces, redirecting
button presses on the device into keystrokes indistinguishable from other
keyboard activity. This prevents (I think?) remapping these keys without
torching the entire system keyboard setup.

  My question is how to approach this?  I'd like to identify this device
specifically and prevent the association with keyboard/mouse drivers,
probably just pumping everything out through evdev for simplicity.  I'm
RTFMing like a madman, but don't want to have to write up yet-another-driver
if I can avoid it (but am willing if it's deemed necessary.)  The absolute
ideal would be to be able to use the same userland tools with both the n50
and n52, so homogenizing the interfaces would be advantageous.

  -P

[1] - http://catalog.belkin.com/IWCatProductPage.process?Product_Id=157024
[2] - http://catalog.belkin.com/IWCatProductPage.process?Product_Id=107727
[3] - http://sourceforge.net/projects/nostromodriver