Email.SetMessageFile(FileName) example

this.EM = new Email();
var ErrVal = this.EM.Create(this);
if (ErrVal >= 0) {
  ...
  this.EM.AddMessageLine ('Sincerely,');
  this.EM.SetMessageFile('U:\\Signature.txt');
  this.EM.SendMessage();
  ...
  this.EM.ClearMessageText();
  this.EM.SetMessageFile('U:\\AutoRespond.txt');
  this.EM.SendMessage();
  ...
}