I am in a process of migratinga small number of users from Ex2003 on SBS2003 to a new forest with Ex2007 installed on a win2008 server. Here is my plan, not sure if this actually would work:1. Install all roles except Edge on one server. 2. Add the same domain name still in use as an accepted domain. 3. Make this an internal relay domain.4. Create a send connector for the same domain name that point to the old Ex2003 server. 5. Create a new virtual SMTP for the same domain name on the old Ex2003 server that points to the new Ex2007 server. 6. Change the default * SMTP server on the old Ex2003 to point to the new Ex2007 server, so that any outgoing mail is relayed trough this. 7. Create a * send connector on the new Ex2007 server for all outgoing mail.8. Change the MX to point to the new Ex2007 server. Would this work?I mean, if incoming mail that enters the new Ex2007 server, the mail is routed to the MB role if the account exists on the server, if no it should be sent to the old Ex2003 server, am I right?And vice versa, if there are incoming mail on the old Ex2003 server that is to recipients that exists only on the new Ex2007 server, it would route the mail to the new server?

Hi,That is the right operation. Additionally, I would like to share more useful resource with you:http://technet.microsoft.com/en-us/library/bb676395.aspxhttp://technet.microsoft.com/en-us/library/bb124423.aspxThanksAllen