Gear VR left and right eye world position

Hello, anybody now how to get the world position for the left and right eye on the Gear VR?

Here is a similiar post : https://community.unity.com/t5/Virtual-Reality/World-positions-of-left-right-eye/m-p/2370871#M8859

but it doesn't seem to work for me, using unity 5.4.2
InputTracking.GetLocalPosition(VRNode.LeftEye) allways returns 0...

any ideas? Thanks for the help!