Raycast a World Space UI with VR (Daydream)

Hello,

need some help with raycasting UI with Daydream. As there are only a demo for gameObjects (cubes), I want to know I can handle UI elements. The UI elements should react as usual, I mean highlighted and so on. The posts in http://stackoverflow.com/questions/39087609/how-to-use-graphic-raycaster-with-worldspace-ui were helpful, but completely.

I used DrawRay to see where my pointer is actually going through and it works good. But no log message is created.

 void Update()
 {
     Quaternion ori = GvrController.Orientation;
     Vector3 vector = ori * Vector3.forward;
     Debug.DrawRay(transform.position, vector * 100000, Color.green);

     PointerEventData pointerData = new PointerEventData(null);
     pointerData.position = vector;
     Debug.Log(vector);

     List<RaycastResult> results = new List<RaycastResult>();
     EventSystem.current.RaycastAll(pointerData, results);
     if (results.Count > 0)
     {
         Debug.Log(results[0]);
     }
 }

Canvas (World Space) and Button is created as useal and not modified.

Thanks for your help!

PS: Maybe @faken or @Umair M reads this and can help.