There isn't a way to hit all users as it's a per user configureation from that Default user object. This was a problem for us. You have to add it to every users profile that is present as well as teh default user profile. That way it's created for new users. It's a limitation to the way the toolbar is used.
paths are as follows...
Loged on user: %userprofile%\Application Data\Microsoft\Internet Explorer\Quick Launch
Default user: C:\Documents and Settings\Default User\Application Data\Microsoft\Internet Explorer\Quick Launch
hope that helps you...