TABLE 1: Return Addresses and Related Mailbox Permissions
To get this sample return address...	Use these permissions on the mailbox...
Customer Support	Send As permission on the mailbox, plus
[support@mycompany.com]	Reviewer permission on the Inbox and root mailbox folder
John Doe [doejo@mycompany.com] on behalf of Customer Support [support@mycompany.com]	Delegate access (which includes Send on Behalf Of permission) to the Inbox, plus Reviewer permission on the root mailbox folder
John Doe [doejo@mycompany.com]	Reviewer permission on the Inbox and root mailbox folder