GUITexture HitTest not registering

OK, I've been trying to get it working for the last hour and it's getting frustrating. I simply want to detect a click on GUITexture (old-style, not new fancy GUI stuff).

I have a GameObject of GUITexture type in the scene - this GameObject is called NoteIcon. The code in main camera Update method is as follows:

 GameObject go = GameObject.Find("NoteIcon");
 GUITexture gt = go.guiTexture;
 bool a = gt.HitTest(Input.mousePosition);
 Debug.Log (a);

a is ALWAYS false, whether I'm clicking on the object or not. Why the hit is not detected properly?