In our workflow, the application prepares a mail in the user's mail box, then opens it using ws.EditDocument(...). Very flexible, albeit with a serious drawback: the mail moves out of my control, meaning that it gets very difficult for the application to find out whether the mail has actually been sent or not. In this case it's even more difficult, because the mail isn't sent from my application but from a mail database. So, I'd like my application to be triggered when a particular mail is sent.
Ideally, the Router should send my application a service mail, a "message", telling it that that mail was sent... and then I'd have an agent handling such messages.
Service messages, in this case as a trigger for "After mail is sent".