In legacy versions of Exchange Server we could use PFDAVAdmin to manage calendar permissions, or alternatively the 3rd party tool SetPerm.
With Exchange Server 2010 calendar permissions can be managed using the *-MailboxFolderPermission cmdlets. While these cmdlets can be used to manage permissions on any mailbox folder, we`ll focus on calendar permissions.
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 firstname.lastname@example.org mailbox-