Are you using the mini-breakout or the Arduino compatible breakout board?
if it's the Arduino breakout board you may start e.g. with the blink sample on mraa/blink-io8.py at master · intel-iot-devkit/mraa · GitHub (just replace IO 8 by 13). If this is working you would need to check further on XDK setup
thanks for responding quickly.
Yes, I'm using the Arduino compatible breakout board.
After I rebooted the Edison it looks like the GPIOs are now accessible :-)