test.cs

public byte[] ExtractSmartDocument(string DocumentName) {

  using (TXTextControl.ServerTextControl tx = new TXTextControl.ServerTextControl()) {

    tx.Create();

    // the load PDF document
    TXTextControl.LoadSettings loadSettings = new LoadSettings();
    tx.Load(DocumentName,
      TXTextControl.StreamType.AdobePDF,
      loadSettings);

    // loop through all attachments to find the original document
    // and the annotations
    foreach (EmbeddedFile file in loadSettings.EmbeddedFiles.Reverse()) {

      if (file.FileName == "original.tx")
        return (byte[])file.Data;
    }
  }

  return null;
}