Unreal Engine not detecting Oculus /Ubuntu/

Hello,
I am working on my bachelor thesis and would like to create extended positional tracking based on RGB camera attached to Oculus (infinite positional tracking). I have algorithms already up and running and would love to merge everything in Unreal Engine. I am running Ubuntu 14.04 and have Oculus SDK 0.5 Up and running - Tuscany demo working well. I do have fully working (after compilation etc.) Unreal Engine 4.7.6 - which does fully support SDK 0.5. I have oculus plugin enabled in my UE project settings as well. However, I am having option “Preview VR” greyed out as if UE was not able to detect Oculus service running.
Would you be so kind and help me with this?
Thank you very very much!