(I'll note, just as a sort of aside, that you can't "legally" put Technet software into production use. This is part of the agreement when you subscribe: Technet software is for development and testing only. So your upgraded PCs aren't, technically, "legal". Not that I care personally, but from the way you phrased that statement I thought you might... :) )
The issue with Windows 7 appears to me to be a result of changes to the Security Center in Windows 7. You can try installing the beta of Pwer Pack 3 for Windows Home Server and see if that helps...
I'm not on the WHS team, I just post a lot. :)