1. Unlike ADM files, ADMX files are not stored in individual GPOs. For domain-based enterprises, a central store location could be created for ADMX files that is accessible by anyone with permission to create or edit.
2. Group Policy tools will continue to recognize custom ADM files you have in your existing environment, but will ignore any ADM file that has been superseded by ADMX files.
3. New Windows Vista-based or Windows Server 2008-based policy settings can be managed only from Windows Vista-based or Windows Server 2008-bsed administrative machines running Group Policy Object Editor or Group Policy Management Console.
4. ADMX file with these new policy settings defined in it will not be exposed on the Windows 2003, Windows XP machines. GPO Editor on such machines cannot be used to modify these policy settings in ADMX and GPMC will display new Windows Vista Administrative Template policy settings as extra registry settings.
5. The Windows Vista or Windows Server 2008 versions of Group Policy Object Editor and Group Policy Management Console can be used to manage all operating systems that support Group Policy (Windows Vista, Windows Server 2008, Windows Server 2003, Windows XP).