Those of us who need to upgrade or migrate our previous ISA environments to the new Microsoft product, called Forefront TMG we will need to perform a migration by import/export configuration, since Forefront TMG only works under 64bit systems or Windows 2008 SP2 or R2 and we will not be able to upgrade it from an earlier version of ISA Server, be ISA 2004 or ISA 2006 (since they run on x86). We will also have to manually export the certificates along with their private key to the TMG, since this process simply migrates the configuration.