MVC 4 RouteValues object containing a List

Hey guys.

I am currently have the following model that contains all the GET parameters my method requires:

public class RequestModel
        public List<int> clients { get; set; }
        public DateTime time { get; set; }
        public int Duration { get; set; }
        public double Rate { get; set; }

But now I need to use the object in a redirect and output it as route values

return RedirectToAction("Index", "Appointments", (AppointmentRedirect)TempData["returnUrl"]);

This works fine for each object in the object, except for the List. The List output is like this:

I need the output to be something like this:

What would be the best / easiest way to achieve this?