Blackberry permissions for Exchange 2007
After installing and configuring the Blackberry Enterprise Server application you will need to run the following Exchange 2007 PowerShell commands to grant the Blackberry service account (besadmin) access to the Exchange mailboxes.
Granting access for a single mailbox
In this example we are giving the besadmin account the access required to handle the email for the john.doe@domain.com mailbox-