Hi Juan,
thanks for your reply. If for sending out the confirmation email (containing the generated link) I have to use a Service Task, do you know where I can find some tutorial ? I found something concerning configuration of a jpbm mail service, but this somehow does not fit to the piccture I yet have.
Further, I think I think the process will start with sending out the email and then going into a user task which needs to be completed by the user the email was sent to. But a task needs a group or a user to whom it is assigned. Where does this ID come from ?