Headphones and Anthem AVM 30

Hello all,

I have an Anthem AVM 30 and I've been struggling to figure out how to configure it so that when I plug in headphones, my 5.1 downgrades to L R (from a dolby digital 5.1 source). The issue is that the headphones are only picking up L R out of L R CENTER LFE LSURR RSURR, so Im losing a lot of the audio if I choose to listen with headphones.

Ive tried muting the speakers automatically when the avm detects headphones are being used, but no, the damn thing still is outputing 5.1.

Ive tried copying the main source to zone 2, and then editing my cinema speaker configuration, but it seems I cant change the configuration for a source for a specific zone, it modifies the main source itself. Intuitively I believe I should be able to modify how a zone takes a source and outputs it, so I suspect this might be where the user error is....

Any help is appreciated, I've scoured the manual for hours and tried quite a number of things, but I can't get it to work.

Thanks,

Rob