http://blogs.technet.com/b/danielkenyon-smith/archive/2011/08/09/enabling-calendar-sharing-office-365.aspxSteps Action Enable free/busy calendar sharing on-premise Run the following command Set-SharingPolicy ‘Default Sharing Policy’ –domains ‘*: CalendarSharingFreeBusySImple’, ‘Company.com:CalendarSharingFreeBusyReviewer, ContactsSharing’, ‘Company.onmicrosoften-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)http://blogs.technet.com/b/danielkenyon-smith/archive/2011/08/09/enabling-calendar-sharing-office-365.aspx#3567891Fri, 19 Apr 2013 13:11:21 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3567891Cristiano Santos<p>You may need to run Enable-OrganizationCustomization on the Exchange Online Organization before running Set-SharingPolicy:</p> <p><a rel="nofollow" target="_new" href="http://technet.microsoft.com/en-us/library/jj200665(v=exchg.150).aspx">technet.microsoft.com/.../jj200665(v=exchg.150).aspx</a></p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3567891" width="1" height="1">