Have you learned anything new about this? I have had this problem as well with Outlook 2007 in enterprise setting. As the meeting organizer, I have access to the Recurrence settings, but I do not get the Cancel Meeting button. Instead, under Actions, I only have the "Save & Close", "Calendar", "Delete", and "Forward" options. And of course, "Delete" only deletes for yourself instead of allowing you to remove from everyone's calendar.
Looking for advice on this topic as well.