/// <remarks/>
 public void retrieveSignatureProofOfDeliveryLetterAsync(SignatureProofOfDeliveryLetterRequest SignatureProofOfDeliveryLetterRequest) {
     this.retrieveSignatureProofOfDeliveryLetterAsync(SignatureProofOfDeliveryLetterRequest, null);
 }
 /// <remarks/>
 public void retrieveSignatureProofOfDeliveryLetterAsync(SignatureProofOfDeliveryLetterRequest SignatureProofOfDeliveryLetterRequest, object userState) {
     if ((this.retrieveSignatureProofOfDeliveryLetterOperationCompleted == null)) {
         this.retrieveSignatureProofOfDeliveryLetterOperationCompleted = new System.Threading.SendOrPostCallback(this.OnretrieveSignatureProofOfDeliveryLetterOperationCompleted);
     }
     this.InvokeAsync("retrieveSignatureProofOfDeliveryLetter", new object[] {
                 SignatureProofOfDeliveryLetterRequest}, this.retrieveSignatureProofOfDeliveryLetterOperationCompleted, userState);
 }