In our case, our final solution was a bit involved, but for us it is robust and keeps everything we need:

1- We mirrored the database(s) into a mirror server.

2- We now take snapshots of the mirror server and leave the principal alone.

3- And of course, we do not do any backups of the mirror server, except the snapshots.

This way the principal is fine and dandy, has a mirror stand-by to fall back to, and we have the snapshots of the mirror to use during Disaster Recovery exercises. Works perfectly in our environment.

Thanks all,

Raphael