For anyone having issues with the A&B buttons being reversed in FBA you can remap game controls.
Press the Start & Select during game play to access the FBA Key Config menu, HOWEVER due to the A & B buttons being swapped around in the PyMenu (not sure why) its a little confusing to get the key config correct, just remember that A & B are reversed
For Street Fighter II I've mapped the following Config:
Fire 1 = X Medium Punch
Fire 2 = Y Light Punch
Fire 3 = L Heavy Punch
Fire 4 = B Medium Kick
Fire 5 = A Light Kick
Fire 6 = R Heavy Kick
This will make the layout for Street Fighter II on the RS-07 control panel the same as below:
Y X L
LP - MP - HP
A B R
LK - MK - HK
FBA will create a Config file, you should be able to copy that file to a PC and rename it the same as other Street Fighter II roms, then place it back in the FBA config folder to save having to map every game.
The ROM that I configured was SF2m7.zip NOte not all SFII games will have the same config some may be trial and error. I will gradually build up a pack of config files for FBA that can be copied to the .fba/configs folder