From the plug:
pin 1 brown
pin 2 red
pin 3 orange
pin 4 yellow
pin 5 green
pin 6 blue
pin 7 purple
pin 8 grey
on the b9g socket
pin 1 brown
pin 2 red
pin 3 orange
pin 4 yellow
pin 5 jumper to pin 8
pin 6 blue
pin 7 purple
pin 8 grey
pin 9 green
all 8 wires from the plug go to the b9g socket.
it's interesting that this mod/add-on is official but no documentation has been found. Probably something base 202 workshop conjured up.