I have been using the helmet locking devise that mounts under the license plate frame and holds two helmets. This lock utilized the "D" rings to lock the helmets. I really enjoy being able to lock the helmet(s) to the bike, as I hate carrying it around. This system has worked well for me!
I just recently purchased a Nolan N90 without realizing that there would be no "D" rings (the N90 uses the Nolan microlock strap) with which to lock the helmet to the bike. Any one out there find away to resolve this issue? If so, I'd sure appreciate knowing how you have accomplished it.