How to copy to Windows 7 Default User Profile?

Today I set up a Windows 7 Professional laptop on a customers network. When I got to the stage of the process where I copy a preconfigured profile to the default user profile the option was greyed out.

Having done a quick bit of research via Google it would seem that it is quite a common issue – but not one for which there seemed to be an answer.

Does anyone know if you can still copy profiles to the default user profile in Windows 7?

Regards
Mark