1° In Outlook 2010 I can't share calendars with the Zimbra Connector for Outlook.

I right click my calendar, go to Sharing... -->Share Calendar...

But the button "Share Calendar" is greyed out...
ImageShack® - Online Photo and Video Hosting

How can i easily share a calendar?

2° When i want to open a shared Calendar, I lookup the owner in the global address list. I find the owner but i can't choose between his calendars.

How can i see the calendars of the user?