Xbox 360 VGA mod

[WGSquallx2002]

I have a question. Has anyone done this mod (perhaps stumbling across articles like the one posted on Engadget)? I've just completed mine and got all colors looking as they should. The problem is, my Xbox 360 doesn't detect the cable as an HD cable even though its connected through VGA. I neglected to solder an optical port and a composite. I also used the wires from the composite cable I hacked as I didn't have any. Would these wires, affect the quality/performance of the VGA connection (even though I get a good picture).

The only display options I have when I have it hooked up to my BenQ FP241W is the resolutions and reference levels. I can't access any high definition mode options although I can set my resolution to 1920x1080. Any ideas people? Thanks.