That monitor is connected a secondary monitor as the PC doubles as a HTPC, but is more generally used with a 24" LG LCD.
Now, I've tried setting it to have the plasma be activated. doesn't make a difference.
However, Microsoft Media Center's Digital Cable Advisor sees it as HDCP enabled. This is very very annoying as it means I can't play many bluray disks directly as they fail the HDCP check.