Google Message Continuity Setup and Administration Guide - Manual (Page 10)

Add Your Exchange Users to Google Apps 13
Add Your Exchange Users to Google
Apps
Chapter 2
Before you begin
Be sure to read “Getting Started” on page 7 for a list of system requirements,
prerequisites, details on how Message Continuity works, and for a description of
these setup steps.
Overview
Add your Exchange users to Google Apps so that Message Continuity knows
which mailboxes to synchronize. You have two options when adding your users:
You can use Google Apps Directory Sync for adding a large number of users, or
you can add your users manually in the Google Apps control panel. See the
sections below for instructions on both of these methods.
IMPORTANT: For Google Message Continuity to function properly, your users
must always be synchronized between Postini and Google Apps. If Google
Message Continuity is configured for one user in Postini, that same user must be
configured in Google Apps. Otherwise, continuity between the two services is
interrupted and data gets out of sync. Therefore, in addition to adding your users
during these setup steps, it's also important to later add new users to Google
Apps as they're added to Postini.
Note: During setup of Message Continuity, you’ll also need to decide whether or
not you want to include historical message data when first synchronizing with
Gmail.
Adding Users with Google Apps Directory Sync
To add a large number of users, we recommend that you use Google Apps
Directory Sync, which enables you to upload mailing lists (groups) and contacts
along with the user accounts. For details, see the following Help Center article:
http://www.google.com/support/a/bin/answer.py?hl=en&answer=106368