My first question would be, why do you have your DVD player connected to your TV with the HDMI? It should be connected to the receiver with the HDMI, than an HDMI from the receiver to the TV.
From there you have the Optical cable connected from the SPIDF out on your TV to either the AV1 or the AV4 optical input.
From there you should be able to switch between the Audio coming out of your TV speakers, or your receiver speakers.
I'm just trying to understand the method to your madness