Send As permission Exchange 2007

A customer asked for assistance as he was having difficulties with providing the "Send-As" permissions in Exchange 2007. To clarify the story i will talk about user A and user B. User B needs to have the send as permission on the mailbox of user A. Our customer provided Full mailbox access, and send as permission for User B on the mailbox of USer A. When User B tries to send a mail from the user A mailbox, User B recieves an error stating that User B has insufficient rights to send as user A. Checking the permissions with Adsiedit and Get-AdPermission proved that User B did indeed have the send as rights. After a small search i found out that users also need the Send-On-behalve permissions:

Powershell:

# Grant "Send on behalf" permission
Set-Mailbox -Id "User A" -GrantSendOnBehalfTo "User B"


# Grant "Send-As" permission
Add-ADPermission -id "User A" -ExtendedRights Send-As -user "User B"


# Grant full mailbox access permission
Add-MailboxPermission -id "User A" -AccessRights FullAccess -user "User B"

Note: You can add multiple users at the same time by using comma's as sepperator.

Gui: