Maybe there's no driver for BootCamp yet? I'm assuming you mean Windows via BootCamp? Have you updated your BootCamp drivers? Virtualized Windows should not have a problem working on the LED ACD.
When I first tried my LED ACD in bootcamp it didn't work. I had to use the monitor property dialog to extend my desktop. Then I used the nVidia widget in the taskbar to turn off the MBP display so that the ACD would be used as the primary.