Bilingual 404 page in MVC4

Successfully made it to work. Thanks to @r.vengadesh and the links I provided in the question. Anyway, here are the files and the modifications within...

Global.asax:

protected void Application_Error(object sender, EventArgs e)
{
    Server.ClearError();
    var routeData = new RouteData();
    HttpContextBase currentContext = new HttpContextWrapper(HttpContext.Current);
    var culture = RouteTable.Routes.GetRouteData(currentContext).Values["culture"];
    routeData.Values["culture"] = culture;
    routeData.Values["controller"] = "Error";

    if ((Context.Server.GetLastError() is HttpException) && ((Context.Server.GetLastError() as HttpException).GetHttpCode() != 404))
    {
        routeData.Values["action"] = "Index";
    }
    else
    {
        Response.StatusCode = 404;
        routeData.Values["action"] = "page404";
    }
    IController errorController = new ErrorController();
    HttpContextWrapper wrapper = new HttpContextWrapper(Context);
    var rc = new System.Web.Routing.RequestContext(wrapper, routeData);
    errorController.Execute(rc);
}

And the RouteConfig:

public class RouteConfig
{
    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

        routes.MapRoute(
            name: "DefaultWithCulture",
            url: "{culture}/{controller}/{action}/{id}",
            defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
            constraints: new { culture = new CultureConstraint(defaultCulture: "en", pattern: "[a-z]{2}") }
        );

        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { culture = "en", controller = "Home", action = "Index", id = UrlParameter.Optional }
        );

        // Catch-all route (for routing misses)
        routes.MapRoute(
            name: "Localized-404",
            url: "{culture}/{*url}",
            defaults: new { controller = "Error", action = "page404" },
            constraints: new { culture = new CultureConstraint(defaultCulture: "en", pattern: "[a-z]{2}") }
        );

        routes.MapRoute(
            name: "Default-404",
            url: "{*url}",
            defaults: new { culture = "en", controller = "Error", action = "page404" }
        );
    }
}

Of course you need to have ErrorController with a page404 inside.