How do you make Estes Shipment Tracking V1.1 API work?

I want to use c# to track Estes shipments using their v1.1 API. I would like to see some working code. I've added a web service using their WSDL.

I have been trying the "essential code" posted June 13 by gridtrak.

  EstesAPI.EstesShipmentTracking_PortTypeClient trackClient = new EstesShipmentTracking_PortTypeClient();
  trackClient.ClientCredentials.UserName.UserName = "********";
  trackClient.ClientCredentials.UserName.Password = "********";

  EstesAPI.search trackSearch = new EstesAPI.search();
  trackSearch.requestID = "Concept"; // + DateTime.Now.Ticks.ToString();
  trackSearch.pro = "0681320577";
  EstesAPI.shipmentTrackingRequest trackRequest = new shipmentTrackingRequest(trackSearch);
  trackRequest.search;
  // How the heck do you make it run?????
  //EstesAPI.shipmentTrackingResponse trackResponse = trackClient.shipmentTracking(trackRequest); // gives error

CS1503 Argument 1: cannot convert from 'EstesWSDL.EstesAPI.shipmentTrackingRequest' to 'EstesWSDL.EstesAPI.search' EstesWSDL c:\Sandbox\EstesWSDL\EstesWSDL\wkmTestForm.aspx.cs 52