Group Policy: Trusted Location in User's My Documents?

I am trying to use group policy to add a subdirectory of the user's home directory as a trusted location for Microsoft Access 2007 (User Configuration/Administrative Templates/Microsoft Office Access 2007/Application Settings/Security/Trust Center/Trusted Locations). However, where I'm having difficulty is that it doesn't seem like the group policy works with a relative path (%userprofile%\My Documents\Subdirectory). Is that true? If so, would a feasible workaround be a loginscript that adds the appropriate registry key?

From serverfault Brett G

• for the logon script way, you should add the path to:

  HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Access\Security\Trusted Locations\LocationX
  

  Where X is the location number

  for %userprofile%, i didn't try yet

  Tony Toews : Just an FYI. You don't actually need to use Locationx after \Trusted Locations\. You can put anything in there that you want such as the name of your application. I would suggest not using Location as some folks may already have some locations defined and conceivably you could wipe thiers out.
  From Mathieu Chateau

• An alternative would be to use the Auto FE Updater. This utility has an option to set the trusted location of the FE automatically. It will also copy down new Access FEs and associated files when updates are made available on the server, create shortcuts and more.

  I would also suggest using a subfolder of the %appdata% aka Application Data folder to store the Access FE and associated files as this is somewhat hidden and thus less likely for the users to muck with the files.

  David W. Fenton : When you recommend AppData are you taking account of the new layout in Vista/Win7 with the roaming folder, which is where this data is supposed to go? How does one determine what folder %appdata% is? Using the environment variable or Windows API?

  Tony Toews : David, I don't know enough about roaming folders in Vista/Win 7. I haven't had any questiohs on that line from the users. In the AutoFEUpdater the %appdata% is the special folder API call using the constant CSIDL_APPDATA and not the environment variable.
  From Tony Toews