VIsta doesent support install fro usb dvd?

I have a Mainboard P5N-T and an pretty new LG external DVD burner connectec by usb 2 and i cant install vista from it, i would imagine vista would support installation from that but it desent seem so, whats wrong?

it boots up the installation program, all be it slowly and later says it cannot find any supported disks to install on or something....

Normally if boot from USB is setup in your bios there should not be any problem.
Apparently the install prog does not recognize your HDD.
Verify in the bios that your HDD is well recognized.
Is the HDD new too?
What is the exact message you receive?