Asp.net mvc 3 - JSON complext object mapping

Refer to http://stackoverflow.com/questions/9610214/pass-complex-json-object-to-an-mvc-3-action

var testViewModel ={
        Name: ko.observable("Joe Bob"),
        Locations: ko.observableArray([
            { ID:1,Name:"Salem, OR"},
            { ID:2,Name:"Big Bear Lake, CA"},
            { ID:3,Name:"Big Bear City, CA"}
        ]),
        Position: ko.observable("Manager")
    }

public class TestModel {
    public int ID {get;set;}
    public string Name {get;set;}
    public ICollection<LocationModel> Locations {get;set}
    public string Position {get;set;}
}

public class  LocationModel{
    public int ID {get;set;}
    public string Name {get;set;}
    public string DisplayText
    { 
        private set; 
        get { 
            return String.Format("({0}) {1}", ID,Name)
        }
    }
}

$.ajax({
    url:'/ClaimsAuthority/Home/TestIt',
    type:'POST',
    contentType:'application/json',
    data: ko.toJSON(testViewModel),
    success: function (data, status, xhr){
        //ko.applyBindings(data);
    }
});