We have an Exchange 2003 server that I'm trying to set up Send As permission on a mailbox with a user that does not have a mailbox on that exchange server or in that domain. I have setup Full Access for the user and that works fine. But when I try to send an email out I get the user does not have permission to send emails out. When I go to set the SendAs permission it only lets me select a user with a mailbox on the same server/domain.
Can this be setup and if yes how would I do it?