In a SBS 2003 Exchange environment, I am trying to setup User A to have Send As permissions for User B. So far I have been able to allow User A to be able to reply to existing messages from User B with the Send As permission in Outlook 2003. When trying to create a new e-mail to Send As User B, User A gets an Undeliverable message error that says that they do not have permission to send to the recipient when the recpeient is not a user on the network.
User A has Send As permissions for User B in the Security Tab in AD. What other permissions need to be set to allow for this?