Delegate Roles for Exchange Server 2007 on a Domain Controller or Member Server-MSExchW

To assign permissions for the backup agent service account

On your Exchange server, from the Start menu, select Programs, Microsoft Exchange Server, and Exchange Management Console.
The Exchange Management Console opens.
Select and right-click the Organization Configuration object. From the pop-up menu, select Add Exchange Administrator.
The Add Exchange Administrator dialog opens.
Click the Browse button to browse to and select the user or group to which you want to assign the role.
Select one of the following options:
- Exchange Organization Administrator role
- Exchange Server Administrative role
Click Add, and then click Finish.

The permissions are assigned to the backup agent service account.