Sadly no. Very VERY few TV's will pass through a digital surround audio signal, and even fewer (in fact I've never heard of any) will take the multichannel audio from a HDMI and pass it out through it's optical output

You could plug the optical from the PS3 into the DAV system and enjoy Dolby Digital and DTS in 5.1 from the PS3, and just have to mute the TV when in use, but unless it has another connection, you won't be able to pipe any audio from your TV to the DAV