How do you use querystrings with ASP.NET routing?

Search(string term, int page)

MapPageRoute("myroute", "myroute/{x}", "~/routehander.aspx")

http://mywebsite.com/myroute/{x}?url=myurl

Dim x as integer = 12
Dim rvd As New Routing.RouteValueDictionary
rvd.Add("x", x)
rvd.Add("url", Server.UrlEncode("/default.aspx"))
HttpContext.Current.ApplicationInstance.Response.RedirectToRoutePermanent("myroute", rvd)

http://mywebsite.com/myroute/12?url=%252fdefault.aspx