I think this link should help you with setting up MVC3 project working with Newtonsoft Json Serializer. For ISO date time formatter you should change the following lines in the JsonNetResult
constructor.
public JsonNetResult()
{
Formatting = Formatting.None;
var settings = new JsonSerializerSettings();
settings.Converters.Add(new IsoDateTimeConverter());
SerializerSettings = settings;
JsonRequestBehavior = JsonRequestBehavior.DenyGet;
}
You have to derive your controllers from BaseController to use the custom result.
hope this helps.