Radeon X1600Pro, 1080i component output and Vista RC1

I installed Vista RC1 and ATI Vista drivers for my X1600Pro video card. I'm using the component output for my HDTV set to 1080i but neither mode fills the screen completely. As a matter of fact I can't tell a different between the standard 1080i mode and the optimized (no overscan) mode, which leads me to believe that for some reason the drivers are stuck in the optimized mode and not switching to full 1920x1080. In the control panel there are 3 buttons - Add, Remove and Apply, but only the Apply button is enabled. It say that I can create a custom mode and use to Add button to add it, but no matter what I do I can't get it to activate. Any help would be appreciated!