Sachin Shah, a PFE from the eastern United States has an interesting walkthrough on migrating Exchange 2007 Managed Folders to Exchange 2010 'Retention Policies’. His blog post is very detailed and has numerous screenshots to explain the process. Check out his post here, and some related tips like this one on the changes in the ‘Send As’ functionality in Exchange 2010 SP2 RU4. This is the kind of vital insight you can expect from Microsoft Premier Field Engineering!