After installing and configuring the Good Server application you will need to run the following Exchange 2007 PowerShell commands to grant the Good service account (goodadmin) access to the Exchange mailboxes.

Granting access

1. Launch Exchange Management Shell. (Do not use Windows
   Powershell.)
2. At the [MSH] prompt, enter:
   [MSH] C:>Get-OrganizationConfig | Add-AdPermission -user GoodAdminName -AccessRights GenericRead -ExtendedRights “Read metabase properties”,”Create named properties in the information store”,”View information store status”,”Administer information store”,”Receive as”,”Send as” Pre-Installation (Exchange 2010)
3. Make sure that the GoodAdmin account is a member of Domain
   Users only.
4. To display the permissions you have set, you can enter the
   following command:
   C:>Get-OrganizationConfig | Get-AdPermission -user GoodAdminName | fl

(source : http://www.good.com/documentation6/QuickInstall_exchange.pdf)