I am experimenting on the HW550-3G with Attitude Adjustment and could programm the LEDs to function as their original intent. I also managed to assign functions to the buttons. Now I also want to start experimenting on the GPIOs. I found out that the following GPIO ports could be managed: 5, 6, 9, 13, 19, 20, 21, 22, 23. I found out wth the following commands to manage one GPIO port.

echo 9 > /sys/class/gpio/export -->to enable gpio port 9
echo "out" > /sys/devices/virtual/gpio/gpio9/direction --> set direction of port, in or out
echo 1 > /sys/devices/virtual/gpio/gpio9/value --> set value to 1
echo 0 > /sys/devices/virtual/gpio/gpio9/value --> set value to 0
cat /sys/devices/virtual/gpio/gpio9/value --> read value of port
cat /sys/kernel/debug/gpio --> Show summary of gpio ports
echo 9 > /sys/class/gpio/unexport --> release gpio port
cat /sys/kernel/debug/gpio--> again show summary of gpio ports

My question is, does anybody have documentation on which pins are assigned to these gpio ports?
Does anybody have experience to connect a relay on these gpio ports?