Outlook 2007 Calendar-cannot share calendar with Free/Busy Permiss

I have a manager that insists that she could share her calendar and give only
Free/Busy permissions and the recipient could only see the blocked times
without being able to open/read anything.
When I try to share my calendar using "Share My Calendar" or manually
entering the Permissions for a recipient, the only way that they can see
anything is if it is set to Reviewer/Full Details. The Free/Busy seems to
work only when using the Scheduling Assistance where it shows you the
recipients blocked times so that meetings don't conflict. I tried copying my
calendar and the Permissions no longer show the Free/Busy option.
Is it possible to share the calendar with only Fee/Busy and no details?