Sorry for not following-up in your topic, but unfortunately in Windows 7 it isn't possible to accurately detect the monitor numbers. I have worked with Microsoft on this issue, and Windows 7 was never built to support reproducing the monitor IDs. I covered this issue in the this topic as well, sorry:
http://www.binaryfortress.com/Forum/index.php?topic=2042.msg9637;topicseen#msg9637