Touch Gui button

How can i change this Object touch button, to a GUItexture touch button.

 function Update () {
       for(var i:int = 0; i < Input.touches.Length; i++)//How many touches do we have?
     {
         var touch:Touch = Input.touches*;//The touch*

var ray:Ray = Camera.main.ScreenPointToRay(touch.position);
var hit:RaycastHit = new RaycastHit();

if(Physics.Raycast(ray,hit, 1000))
{
if(hit.collider.gameObject == this.gameObject)
{
switch(touch.phase)
{
case TouchPhase.Began://if the touch begins
Application.LoadLevel("CENA2 ");
break;
}
}
}

}

}

OnMouseDown() works with touch and GUITextures, so you can do:

function OnMouseDown() {
     Application.LoadLevel("CENA2     ");
}

If you want to use your current code, you can use GUITexture.HitTest() instead of Physics.Raycast().