In order to have a controller working you need:
1) Have a matching HID autoconfig file in autoconfig/hid for your controller.
2) Create a "connect" driver for the pad in "input/connect" folder (source code of RA).
3) Once you are in RA, change the joystick driver to HID and restart.
4) You may be now able to use you USB HID compatible pad in RA.
I included some "connect" drivers as an example. It also need to include them for compilation.