While adding the User State Migration Tool (USMT) to Horizon Mirage is a pretty straight forward task it isn’t documented in any way.
Update: Since version 4.3 the method to import USMT into Mirage is now covered by the official documentation. If you like a more detailed description with pictures this article is still worth reading.
First of all Mirage in the current version (4.x) only supports USMT version 4.0. To get this USMT version you first have to download the Windows Automated Installation Kit for Windows 7 (WAIK) from Microsoft. This download may take a while as the complete kit is around 2 gigs.
After WAIK is downloaded you have to install it. After the installation you will find the USMT sources under C:Program FilesWindows AIKToolsUSMT.
Unfortunately the version of USMT 4.0 which is included in WAIK doesn’t support Office 2010. If you need Office 2010 support you have to download the USMT 4.0 update.
After this is done you have to place the files contained in the update inside the USMT folder and replace the files loadstate.exe, migapp.xml, migcore.dll and scanstate.exe in the x86 respectively in the x64 folder.
After you have merged the update to the USMT folder it is time to import USMT using the Mirage management console.
After the import Mirage now automatically migrates settings and files when doing a Windows XP/Vista to Windows 7 migration.