X-Arcade stick button mapping

[Dave3d]

Hello.

New here, to both ppsspp on PC (I have tried it on my S3, but it doesnt work well with my games), and to the X-Arcade stick.

So, I saw the beginners guide on how to go through the options, and saw a:
"Key Mapping (In Recent Builds)

Is the option that you can map the buttons for your joystick. Still in not working in all joysticks. To map you need touch/click in an key, and after in an buton of your joystick." entry.

http://forums.ppsspp.org/showthread.php?tid=5352

How do we do this?
My sticks dont work at all (I have the dual joystick X-Arcade, http://www.xgaming.com/store/arcade-joys...-joystick/ ), and 1 button on the left side jumps, and 2 buttons on the right side fire and throw grenade (trying to play Metal Slug 1).

Is there a cfg file I could map the keys with?
I know my joystick and button keys (I can open a text file, and do UP, and it will show '8', down is '2', etc etc etc).

So, I would really like to use this joystick, as it is really well built and responsive.
Is there any way to do it?

Thanks.

Dave