This file contains a white paper and PowerShell scripts to provide the recommended and supported migration path from HMC 4.5 to Microsoft Exchange Server 2010 SP2. The steps in this guide may also be helpful when migrating from non-HMC environments that have configured some form of multi-tenancy.
Download it from http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=28714
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