Issue in the header of the MailMessage PST file

Hi Team,

Just for a reference , I am using the following simple code to create my PST file

Please see the attachment, it is showing This message has not been sent.

                                MailMessage emlx = new MailMessage();

                                emlx.ReplyToList.Add("reply@reply.com");
                                emlx.From = "sender@sender.com";
                                emlx.To.Add("receiver1@receiver.com");
                                emlx.CC.Add("receiver2@receiver.com");
                                emlx.Bcc.Add("receiver3@receiver.com");

                                emlx.Subject = "test mail";
                                emlx.Date = new System.DateTime(2006, 3, 6);

                                

                                Aspose.Email.Mime.HeaderCollection cc=new         Aspose.Email.Mime.HeaderCollection();
                                cc.Set("PR_MESSAGE_DELIVERY_TIME", "06-06-2015 13:35:59");
                                emlx.Headers.Add(cc);

                               
                                emlx.XMailer = "Aspose.Email";
                                emlx.Headers.Add("secret-header", "mystery");


    MapiMessage emlMapi = MapiMessage.FromMailMessage(emlx);
                               
                                    MapiProperty ClientSubmitTime = new MapiProperty(MapiPropertyTag.PR_CLIENT_SUBMIT_TIME, convertDateTime(new DateTime(2013, 9, 11)));   
                                    emlMapi.SetProperty(ClientSubmitTime);
                                    MapiProperty DeliveryTime = new MapiProperty(MapiPropertyTag.PR_MESSAGE_DELIVERY_TIME, convertDateTime(new DateTime(2013, 9, 11)));
                                    emlMapi.SetProperty(DeliveryTime);

                                    folder.AddMessage(emlMapi);


Now the issue is, when I open this PST in the outlook, It shows me the error

This message has not been sent    (where as it should show the date when message got received)

Is there any header which I am missing??

Please help, it's really very urgent.