When trying to connect to a 'shared' e-mail account follow the below steps
to properly configure your Outlook 2010 or 2007 client:
1. In the email view right-click on your Exchange account (i.e. firstname.lastname@example.org)
and choose "Data File Properties..."
2. Click "Advanced..."
3. Click "Advanced" tab
4. Click "Add" then type the 'username' of the shared e-mail account
and click both 'OK' buttons.
5. The new mailbox should now appear in the left pane.