[ This article is also posted at ElMajdal.Net website : http://www.elmajdal.net/ISAServer/Upgrading_TMG_Server_2010_Standard_Edition_To_Enterprise_Edition.aspx ]
With TMG Server 2010, upgrading from TMG 2010 Standard Edition to Enterprise Edition is a very easy step. You do not have to uninstall the Standard Edition and then import the policies/configuration that you've had exported previously into your newly installed Enterprise Edition. The upgrade process is simply done by entering the Enterprise Edition product key inside the Standard Edition Management console. Let's see how.
I have installed TMG 2010 Standard Edition, and now will upgrade it to Enterprise Edition, to do this, follow the below steps:
The process of upgrading TMG Server 2010 Standard Edition to Enterprise Edition is very easy. Neither reinstallation is required nor re-importing policies. It is simply done by typing the Enterprise Edition product key, and instantly the Enterprise Edition features will become available.