Ok, I solved it. I implemented an EventArgs action in the interface and delegated the responsibility of doing redirections to the presenter in the following way:
public interface IAddToCartView : IView
{
event Action DoPurchase;
event Action DoAddToWishList;
event Action RedirectToWishListPage;
...
}
Then, I created an INavigator interface which exposes a method "Redirect", and implemented by a Navigator class through Inversion of Control with Ninject. This way I could also abstract the details of HTTPContext from the presenter class.