HD TV and UBS Connection

[Weedguru Higher]

I have an HD TV equipped with an amplifier and surround sound system. There's a USB port on my TV so I figured I could plug a USB key loaded with music into the TV and have the sound come out from the amplifier. Well, it ain't working like I thought. I plugged in the USB key and yes it does play, but only through the tv, not through the amplifier. How the hell do I get the music to play through the amp, and not the tv speakers?

[Ikku]

Doesn't the HDTV have an audio output cable going to the amplifier? And the amplifier/receiver set up to play that audio output? I mean if your TV normally plays through the amplifier and surround sound, its weird that the audio from the USB doesn't just go through the same channels