When I schedule a meeting I can see his availability in the schedule view and my contact is able to do that as well on his end.
Now, when I try to open his calendar (Add Shared Calendar, then typing his emailadres) in Outlook, I get a "You do not have permission to view this calendar". Inside an organization I would see the calendar but availability only.
Do I understand this correct that to open the shared calendar from my contact, he has to add me to the Sharing Permissions of his calendar? And likewise, for him to see my calendar, I add him to my Sharing Permission?
It doesn't specifically mention whether its for internal or external users, or both. Have you tested this? Outlook for MAC has always been different from the rest of the Outlook family in terms of features and functionality. I would interested to see if the above article works.