This is now confirmed as happened from June 10th to September 30th in the Studios next year. Covering the Marvel films, they're promising never before seen characters. The centre piece is the new stunt show replacing CInemagique that will apparently be a 360 show using both live action performers and projections.
The other key parts will be meet and greets (Thor, Iron Man, Captain America, Star Lord, Black Widow...) and shows that presumably will be a replacement for the current Star Wars stage show there.