How is your setup configured? Is the HDMI going through the receiver or through the television? My recommendation would be to hook an Anynet+ device up directly to another Anynet+ device.
I might suggest running everything directly to the television and then run your optical audio from the television to the receiver.
I run Bell Expressvu satellite (PVR) and have a Samsung HT-AS720S receiver with a 46" Samsung LCD 530 (Series 5) connected via hdmi cables (1.3).
I have Anynet+ turned on and working on both devices. When I turn on the TV within 5-10 seconds, the receiver automatically switches from input 'SAT HDMI2' to 'SAT OPTIC2' or 'CD OPTIC2'. Of course this results in a black screen with no audio. We then have to press the input mode each time to get the receiver back to 'SAT HDMI2'.
We do not use the TV speakers, we only use the Receiver for audio. When I disable Anynet+ this problem doesn't occur, but of course without it on, I then cannot use the volume control on the satellite remote as it turns up the TV, not the receiver.