Well see Win7 and Vista customization is VERY different! They are not adding those via a file they are put DIRECTLY into the mounted wims regisry. It is possible, but not trivial. You would need to mount the image, use REGEDIT to load the registry hives (e.g. c:\mount\windows\system32\config\software), make your changes, unload the registry hives, and then commit the changes to the WIM.