Hey Irina,
What I’m saying is that yes, the calendar does not support the example you provided in #1 in your reply above.
However, you do not need to set your “permalinks” settings in WordPress to “%postname%”.
• No matter what the settings in the WordPress “permalinks” page are, the outcome for events should be what wrote in #2 in your example above. So if you use “/%year%/%month%/%day%” etc., this format will affect other permalinks on your site, but events permalinks will remain like wrote in #2 in your example above no matter what option you use.
• There is no support, however, for the sort of custom permalinks plugin you were using in addition to the main WordPress settings.
I hope this helps!
George