callbacks

Is it possible for me add a custom attribute to the payload we receive during the callback even notification? I have multiple applications using event notifications, so I'd like a custom attribute to indicate which application the even notification should be forwarded too.

If not, is there any way I can update the message variable during package creation? I'm referring to the payload below:

It would be really great to have more/better callbacks during the customer signature process. For example, when the document is opened, when the customer Accepts the "Electronic Disclosures", etc... This way, we can contact the customer while they are reviewing the app and answer their questions. This is common on other electronic signature systems. :)