I've been following the migration guide at http://www.it-book.co.uk/1651/migration-from-sbs-2003-to-sbs-2011-3.
The option "Migrate Exchange mailbox and settings" links me to http://technet.microsoft.com/en-us/library/gg563803.aspx
When I get to the stage of right-clicking "Move All Replicas", it instantly hangs.
I can't see anything specifically in the event viewer at the time this happens.
Is this a case of waiting, or is there something more going on here?