SOLVED: Soft Power On SIM900 module - JP pads missing! I have this SIM900 board and working just fine.
But i can't find a way to soft power on this board from arduino.
I read for JP pads. They need soldering first, but from my board this JP pads missing.
Know someone other way to soft power on this from arduino?
OK for anyone who has the same problem. I solved this by soldering a cable on the underside of the board on this pin (see image) on power button. Then I connect the cable to pin 9 on Arduino and run this on sketch:    

  pinMode(9, OUTPUT); 
  digitalWrite(9,LOW);
  delay(1000);
  digitalWrite(9,HIGH);
  delay(2000);
  pinMode(9, INPUT);


I don't know how it works, but it solves my problem.