Ok, so this is how it works for me.

I have set Mail for Exchange to *not* sync automatically, but I want to go to the Email application and from there do a "Send & Receive". I assumed this would also update my Calendar as in the settings for Mail for Exchange I have "Synchronise calendar and tasks" enabled. Is my assumption correct?

I can't see a way to manually request a calendar update from the Calendar application.

Also in Mail for Exchange settings I see "Last syncronisation" as "Today, ...". And as I said earlier "Synchronise manually" from Mail for Exchange settings syncs my calendar as well.

So my question would be now that is it required to have automatic sync enabled in order for the calendar to also be synced?

Yes, I am using Exchange Server 2007.