Currently there is no Win32 API function that supports explicit setting of time stamps on registry keys. The only method to implicitly set time stamps is to write or update keys after having changed the system clock to the desired time. In real this might come along with some unforeseen consequences.

However there is an undocumented NT native API call that allows you to explicitly set the time stamp of a registry key. By utilizing the RegTimeStamp.Dll (that makes that function available to you) you can read and write time stamps on various registry keys from a VBScript or any other scripting language. To write registry time stamps you normally need admnistrative privileges or at least full control on that key.

For example when inserting new servers into an existing farm it is now possible to set the time stamps of all shadow keys to the time stamps of an already existing server. With that you ensure that existing user settings are not overwritten by default settings from the shadow registry of the new server.