Set Exchange 2013 calendar permissions with Outlook 2007

Hi,

I have a new install of Exchange 2013 with ~30 Win 7, Office 2007 clients. Setting permissions on calendars doesn't work properly from Outlook 2007 (a known MS issue). Does anyone know if there is a fix or work around to assign permissions to the calendar? i.e. where you right click the Calendar folder and set different levels of permission. There is a 'permission' option in OWA but this doesnt appear to work for calendars.

I have tried Outlook 2013 and that works ok.  Is there alternate way to save having to move to Outlook 2013?

Thanks.