Share attachment and text from metro app

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C#

Metro-design

I am working on a metro app with c#. I want to share some attachment with subject and mail body to mailto application.
I code like this

DataRequest request = args.Request;
                   DataRequestDeferral deferral = request.GetDeferral();

                   request.Data.Properties.Title = Constants.EMAIL_SUBJECT;
                   request.Data.SetText(Constants.EMAIL_TEXT);
                   var smiFile = await Windows.Storage.ApplicationData.Current.LocalFolder.GetFileAsync(Constants.SMI_FILE);
                   List<IStorageItem> lstItems = new List<IStorageItem>();
                   lstItems.Add(smiFile);
                   if (lstItems.Count > 0)
                   {
                       request.Data.SetStorageItems(lstItems);
                   }
                   deferral.Complete();

When I open mailto app in share charm it only shows attachment with blank subject and body. And in second scenario if I remove attachment then subject and body appears. Why this is happening I want complete mail to send.