finally got it working…. its a big thread that… but the bit you are looking for steve is:

in command line, type – cd boot
sudo nano cmdline.txt

add this line of text
usbhid.quirks=0x16c0:0x05e1:0x040

make sure you save.

reboot. It should now recognise the xin-mo as two controls.

then in the retroarch.cfg file i added what floob told me to as above.