The OpenMSG folk are going to jump in soon, either here or in a new thread ...
Hmmm...Malte, do you have a box running ACES up? If so, Michael could look at its general alerts page to get a sense of how things exist now. The basic change is that you will in the future need to be able to set the kind of alert you want to receive (e-mail, SMS) as well as frequency and all that.