Getting my first solo recorded on video was something that was really important to me as well.
I just left the camera with my instructor and he did a cracking job of it as he watched from the tower. I don't think an in flight video would have been as good, plus you'll have far too many other things to occupy your mind.
When I show it to people now I think they've got more interest in seeing it from the outside than they would have had if it was a cockpit view.. Plenty of time for in flight videos after you've done it