Need script to "opt in" machines for sharing by regular users

In looking at p. 310 of the Windows Vista Adminstrator's Pocket Consultant it
states that an administrator can opt-in a computer for sharing other
resources by regular users by sharing a single file within their own profile.
This then allows a regular user to create shares within their profile
without administrative permissions. I'm looking to automate this procedure
and am finding that by doing this via the GUI that the OS must do something
in the background because when I script it I don't get the same results. A
simple net share statement that creates the equivalent share that the GUI
ultimately creates at C:\Users doesn't yield the same outcome.

Does anyone know how to script this and get the same outcome as doing it
manually via the GUI?