Вооьбще очень странно. А если так:
Код:
CrmDateTimeProperty new_cargo_receive_date = newCrmDateTimeProperty();
new_cargo_receive_date.Name = "new_cargo_receive_date";
new_cargo_receive_date.Value = new CrmDateTime();
new_cargo_receive_date.Value.Value = Convert.ToDateTime(Request.Params["createdata"]).ToString("MM.dd.yyyy hh:mm");