Question : You do not have permission  to send the message on behalf of the specified user

I have a common computer that logs in locally (it has an AD account with no Exchange mailbox).  I want to be able to use another account in Outlook to send/receive mail.  I setup the Outlook account but when I try to send an email I get a message "You do not have permission  to send the message on behalf of the specified user".  The computer login is Bloomberg, the Outlook is setup for the users WBL2.  I went to the WBL2 account properties and gave mailbox rights to Bloomberg but still got the same message.

What am I missing here?

Answer : You do not have permission  to send the message on behalf of the specified user

yes the user should be logged on as domain user.
The basic concept is this... The sender should altleast be mail enabled inorder to have send as permission from another mailbox. Then you will see that in the list.
How did you configure the profile on the common/local computer
did you specify it as bloomberg domain user or local user?