Gear VR menu/hud will not appear

I have a simple test map and try to show a menu blended over the game, in my case a few simple buttons to click it.
To activate the menu I take the android-back-node inside the level blueprint. But pushing the back-button on the gear vr
the oculus home question appears instead of my menu.
I switched off all plug-ins except the gear vr and the oculus library.

Thanks for a advice.

Here you go:
Behavior was changed in 4.11 and you gotta use the console command given in the answers to control the back button

Thanks aussieburger.
I followed the steps but how is the connection inside the blueprint?
Connected like this it doesn´t work.