The way you have the boxes connected, (Please don't say 'hooked up'. It is a meaningless expression that some people use to sound clever.) in order for your TV sound to play through the Home Cinema system you TV needs to be able to output its sound to the home cinema system va the scart connector. It may be able to do that but you need to chcek the TVs manual to see if it can. The other way to get the sound from the TV is to use 'Phono' plugs and leads. Your TV's manual will also say whether you can do that. Finally if the TV can output sound, either way, you need the home cinema system to be on the right set of plugs to input it. The home cinema manual will say what to do to use the TV's input rather than the DVD player's.
Terry
May 2006