To enable import and export of mailboxes on SBS 2011 you need to:

Go to Windows SBS console and create a security group – that shuld be universal (by default) for example: Mailbox management

Add administrator / admin account to the group

Then you need to enable “import / export” feature on members of this group. To do that you need to open Exchange Management Shell (Powershell with Exchange 2010 modules) as administrator and write:

New-ManagementRoleAssignment -Name “Import Export Mailbox Admins” -SecurityGroup “Mailbox management” -Role “Mailbox Import Export”

After that you can folow my article to import or export mailboxes…