If you are planning to install Blackberry services in your environment then you have to consider permissions required by BB on Exchange setup.
BB required following set of rights in order to perform operations on user mailboxes;
1. Send-As permissions on user mailboxes.
2. Receive-As permissions on mailboxes.
3. Ms-Exch-Store-Admin permissions.
You have to provide the above permissions to blackberry service accounts; following is the method for doing this;
Provide View only Admin rights to BlackBerry Service Account
get-mailboxserver <mail_server_name> | add-exchangeadministrator BESAdmin –role ViewOnlyAdmin
Provide Send-As, Receive-As and MS-Exch-Store-Admin to BlackBerry service Account.
get-mailboxserver <mail_server_name> | add-adpermission –user BESAdmin –accessrights ExtendedRight –extendedrights Send-As, Receive-As, ms-Exch-Store-Admin