How can you detect the oculus home overlay without the OVR manager?

I'm in the polishing stages of my VR game using Unity, and I cannot seem to find away to make use of the VR utils to detect :

A- The oculus overlay's presence

B- The headset's presence on the user's face.

I want to be able to pause my game and resume it based on these events. Unity's sample scenes do not offer any insight in this matter.

It seems that the OVR manager script does support this functionality, but it limits support with other vr headsets by making my code more platform specific, in addition to breaking all my image effects.