Change values in a ASP.MVC View between the controller parameter object and the object that will be post.

Question

Hi, I have the next controller:

 public ViewResult AddPresentation(string categoryKey)
    {
        Category category = new Category();
        category = repository.GetCategoryByKey(categoryKey);
        return View(category);
    }

In the "AddPresentationView" I have to fill some object properties with values from the "AddPresentationController" parameter: "category". Then I will post this new object:

    [AcceptVerbs(HttpVerbs.Post)]
    public ViewResult AddPresentation(Presentation newObject)
    {      
    ....
    }

In a few word: I want to put in "newObject" properties, values from "category" object in the AddPresentationView.

Thank you for patience...and for answers.