Creating callback event for Mobile device signature request email

Here is the situation : We integrated OneSpan eSign into our Saas. As we wanted it completely withelabeled, we integrated the designer into an iFrame and we use the callback events listed here: https://docs.esignlive.com/content/c_integrator_s_guide/sdk/i_reports_and_logging/event_notifications.htm?Highlight=callback to send our email instead of OneSpan emails. The thing is there is an important email without any callback event. The email is triggered when a signer wants to sign with his mobile device using the "sign with your mobile device" button (see attachments). We would like to have a callback event for that specific email. Is there a way we can create it ?