json not passing thru id on mvc 3 controller

Question

I have the following controller

[HttpPost]
public JsonResult Update(List<DeliveryNoteDisplay> DeliveryNotes, UserSession userSession)
{
// etc
}

This passing thru all of values correctly with the one exception that the id value is alway null even though i can see it via fire bug.

public class DeliveryNoteDisplay
{
    public virtual string Id { get; set; }
    public virtual string ProjectId { get; set; }
    public virtual string DeliveryNoteId { get; set; }
    public virtual string ClientId { get; set; }
    public virtual string VehicleId { get; set; }
    public virtual string CourierId { get; set; }
    public virtual string JobIds { get; set; }
    public virtual string Name { get; set; }
    public virtual string DeliveryTo { get; set; }
    public virtual string DeliveryFrom { get; set; }
    public virtual string Estimated { get; set; }
    public virtual string Actual { get; set; }
    public virtual string BookedDate { get; set; }
    public virtual string CreatedByUserName { get; set; }
    public virtual string Modified { get; set; }
    public virtual string Created { get; set; }
    public virtual bool ShowAddressFooter { get; set; }
    public virtual bool ShowDeliveryFrom { get; set; }
    public virtual bool ShowHeaderLogo { get; set; }
}

Answer 1

In the post the json starts with Id with a value and ends with id again... there it's empty.