Here is an example file that should be placed here:
/opt/retropie/configs/all/retroarch-joypads
http://pastebin.com/raw.php?i=vYP9xSeF
You can get the input_device value by looking at the “iproduct” value.
use “lsusb -v”
Or for a specific device, like this
“sudo lsusb -D /dev/bus/usb/001/004”
because mine is the 4th device on the usb bus
Anyway… not sure if it will work but you can try.