Routing in MVC2. Attributes are not displayed

Good time! There was a problem displaying the route in the input URL browser. To the search page on the site. The search itself is working fine - the "key" is passed, the list of found displayed. Search method in the controller takes an argument of type string for which to search:

    public ActionResult SearchAllByKey(string key)

            {

                //logic

                return View();

            } 

In Global.asax prescribed route:

    routes.MapRoute(

                      "Search",

                      "Search/{key}",

                      new { controller = "controller_name", action = "SearchAllByKey", key = UrlParameter.Optional }

                  );

Form which sends the value of Edit to method from View:

    <% using (Html.BeginForm("SearchAllByKey", "controller_name", FormMethod.Post, new { enctype = "multipart/form-data" }))

                               {%>

                            <%: Html.ValidationSummary(true) %>

                            <% } %>

When you click on "Go!". to a page of search results, but the URL (input line browser) shows:

    http://localhost:PORT/Search

instead of:

    http://localhost:PORT/Search/SOME_KEY

How to make sure that was visible "key" in the URL-e? Thanks in advance