GSM SIMCOM SIM900 Development Board Wiring to Arduino

I bought this board from the idea of building a remote control for an irrigation water pump that could be easily controlled by making a phone call or via SMS:

Once I received it I noticed it had no pins underneath, so it wasn't really an Arduino SHIELD.
I found out this tutorial:
http://tronixstuff.com/2014/01/08/tutorial-arduino-and-sim900-gsm-modules/
But didn't clarify the connections, so I figured out that in this particular board, the connections are as follows:
Opposed to the tutorial, this is the switch position for external power supply:

Ground is correct, just lay a bridge between GND from the arduino board to the second pin from the end of the GSM board:

Time for RX and TX connections:

Since you won't be plugging the board to the arduino, just take out the jumpers and plug them as the image states. If you insist on keeping the jumpers, beware that they have been labeled wrong. These are the actual links:

From now on, you should have no problem on following the examples of the tutorial mentioned before, as long as you power on the board manually. If you want to add functionality to Software Power On, you should solder these pins to power the device through D9:

This link will make D9 exclusive for power on/off. If you want to use another output, don't solder both pins, just link the terminal circled in red to the desired arduino output.

Hope this article helps someone.