I am a network admin for Domain A, which is the forest root. We have aquired another company and added them to our forest as another domain tree, Domain B. We are a Server 2003 organization, using Exchange Server 2003. We are also connected via 1.5mbps MPLS. We have a Mail Server here, and also one at the remote site. All traffic, for both domains come through a pair of Cisco ASA 5510. I want to move all the mailboxes from Domain B to the Mail server located at Domain A and decomission the Mail server at Domain B. What is the best way to do the mailbox migration, and what issues do I need to be aware of as we move forward?