I switched a few minutes ago to this calendar plugin because I need full polylang support. Apparently, this is precisely what I was looking for.
After installing, I saw in the setting page links to faq and tutorials, which disappeared after some customisation... and google was not able to bring me back to them. ?!?
The small detail I was up to is: how to define different date formats for different languages (example: "May 15, 2014" in English, but "15 maggio 2014" in Italian).