Sorry
This is definitely not possible. You can definitely run your app during a call (no tombstone concern), but WP takes over the mic for a phone call. Your app will run, but you'll get perfect silence recorded. This is by design. It would be great if they change it at some point. Obviously the user should have to OK something, but the concern is about the other party since some US states (not sure of other countries) require that both parties are notified of a recording in progress.
---------- Post added at 12:55 PM ---------- Previous post was at 12:49 PM ----------
This is definitely not possible. You can run your app during a call (no tombstone concern), but WP takes over the mic for a phone call. Your app will run, but you'll get perfect silence recorded. This is by design. It would be great if MS changes it at some point. Obviously the user should have to OK something, but the concern is about the other party since some US states (not sure of other countries) require that both parties are notified of a recording in progress.