Iphone joystick where player touches

I know this might have been discussed elsewhere but honeslty, i couldn't find a thing!

All i want is to make the joystick appear wherever the player touches (like i.e. in Predators game ).

I am using the built-in joystick script. I tried changing its position on update but although the stick appears where i touch, the controls do not correspond to that position.

The following is the code i added to the Joystick.js script inside Update ( tried to make it work both with touch and mouse ).

//Position joystick wherever clicked/touched
   if ( Application.platform != RuntimePlatform.IPhonePlayer ){
     if(Input.GetMouseButtonDown(0)){
       var screenPos=Camera.main.ScreenToViewportPoint(Input.mousePosition);
       transform.position.x=Mathf.Abs(screenPos.x);
       transform.position.y=Mathf.Abs(screenPos.y);
     }
   }
   else {
    if ( Input.touchCount > 0 ){
      screenPos = Camera.main.ScreenToViewportPoint(Input.GetTouch(0).position);
      transform.position.x=Mathf.Abs(screenPos.x);
      transform.position.y=Mathf.Abs(screenPos.y);
    }
   }

Any ideas/scripts/resources i should check?

If anyone done this before PLEASE answer.

Thank you!!!