Controller Interaction with UI

Is there a help/script which shows me how to interact with the controller and UI elements? In the controller demo is only the the Physics Raycaster with game objects used.

I think I have to use the Graphics Raycaster, but how?

At the moment I was able to use the DrawRay to confirm whether the controller goes trough the button. And yes, it does. I expected a log entry while moving the controller over the button and his collider (do i actually need a collider?).

Code (CSharp):

1.     void Update()
2.     {
3.         Quaternion ori = GvrController.Orientation;
4.         Vector3 vector = ori * Vector3.forward;
5.         Debug.DrawRay(transform.position, vector * 100000, Color.green);
6.  
7.         PointerEventData pointerData = new PointerEventData(EventSystem.current);
8.         pointerData.position = vector;
9.  
10.         List<RaycastResult> results = new List<RaycastResult>();
11.         EventSystem.current.RaycastAll(pointerData, results);
12.         if (results.Count > 0)
13.         {
14.             Debug.Log(results[0]);
15.         }
16.     }

Thank you!