OK, just to check - when you tried my suggestion, did you definitely connect the PS3's audio connectors to the "DVI audio in" on the back of the TV (& not the TV's separate L & R audio inputs for its AV channel)?
The photo in your link shows it as a single stereo socket ("DVI audio in") - presumably 3.5mm - so you'd need an adaptor of some sort to take the red & white stereo phono jacks of the PS3's AV lead & connect them to that single socket, e.g.
http://www.maplin.co.uk/Module.aspx?ModuleNo=48366 if it's a 3.5mm stereo socket.