Hello!
I just recently upgraded my Exchange 2003 server. Send as permissions are working fine on all users but the admins. I have followed the instructions from microsoft but still it doesnt work, here's the instruction, taken from
http://support.microsoft.com/kb/912918:
Start the Active Directory Users and Computers management console.
2. On the View menu, make sure that the Advanced Features option is selected. If this option is not selected, the Security page will not be visible for User account objects.
3. Create an ordinary user account to act as the mailbox owner.
4. Assign the ordinary user account a mailbox on an Exchange server.
5. Open the properties of the new mailbox owner account.
6. In the Exchange Advanced box, grant the Full Mailbox Access permission to the protected administrator account.
7. In the Security page, grant the Send As permission to the protected administrator account.
8. Click OK to exit the properties of the mailbox owner object.
9. Right-click the mailbox owner account object, and then click Disable Account to disable the account for all logons.
Instead of creating a new account I just used my support account, I guess that shouldn't change anything. Any other ideas why it won't work?