I have exactly the same problem.
Using a Intel® PRO/1000 GT under Windows XP with the registry setting from http://www.intel.com/support/network/sb/cs-005897.htm works.
Under Windows 7 64 I cannot manage to make it work.
I also found this one: http://communities.intel.com/message/127879#127879 to set the MonitorMode to 2, which I will try now. But it is not really documented somewhere.
So if you could solve the problem, please let me know!