Google Message Continuity Setup and Administration Guide - Manual (Page 19)

Set Up Dual Delivery 23
4. Click Delivery Mgr.
5. On the gray bar near the top of the screen, click Edit.
6. In the Email Servers and Load Balancing section, make sure that Use my
own email server is selected. This is your primary mail server.
7. From the Dual Delivery Server section, select the Enable Dual Delivery
check box, and select the Send a copy to Google Apps Gmail radio button.
8. At the bottom of the page, click Submit to save the changes.
Now that you have set up Dual Delivery in the Postini Administration Console, it’s
time to install the Message Continuity Sync Server.