Chang registry permission w/ loginscript

I would like to change the permissions of Windows XP Pro PCs HKEY_CLASSES_ROOT\outlook to allow a change to the command subkey thought NT Server login script. Domain Users don't have enough rights to make the change. The login script works if logged in as administrator. Policies are not in place. Using REGINI to make the permission change; even tried RUNAS "regini" command line to attempt to grant rights. After change to subkey is made, I will then remove the rights.
Thanks!