Olivia Munn's role in Iron man 2?

Ok, so for weeks now EVERYONE was thinking Olivia Munn was going to play the Iron Madien in Iron Man 2, but now theres rumors that shes going to be playing the Scarlet Witch ! Because people think shes going to be in the film as a quick cameo to kind of advertise the new averger movie? Is this just a rumor, because I mean on http://www.imdb.com/title/tt1228705/ it states she plays Iron madien. Is everything true on imdb.com?