1/ Please move your question to Products where it belongs. The specified item was not found. is for generic Marketing questions and you will get more answers on Products. The move button is in the right pane of the screen.
2/ The Marketo system has this limitation indeed. AFAIK, there are some launch point solutions that might be able to help here and some alternative ways have also been discussed in the community, if you run a search on "ical", you might find your way