ATi TV Out - Why is it bordered?

Hi,

I have a Radeon 8500 and have connected it to my TV with the S-Video connections. It works fine and after some messing about i managed to get Theatre Mode running ok. My main problem is the fact that the display is bordered, just like a crap PAL console conversion is. It makes watching full screen movies a pain, not to mention games and other stuff.

Can anyone tell me why it's bordered at all and not fullscreen 50/60Hz and also if there's a way around this problem.

I tried adjusting the screen using the vertical and horizontal adjustments in the TV Display Settings in the ATi Control Panel, but they dont do anything.

Am i doing something wrong, or is there an Overscan or fullscreen option somehere?

Thanks for any help!