How to attach a chin strap ... you could try glueing straps and maybe velcro, but what I did was go to the local sports store and get a kit for hockey helmets.I drilled a hole on each side of the headset which allowed me to put a metal snap in, and then got a strap and fed it thru a plastic thingie on each end, which snaps onto the metal.
I'm pretty sure Dave Clark sells a kit to do this, too.
Most other people go the route of the "Snoopy Helmet" but I am reluctant to go that path for pretty much inexplicable reasons. I didn't shave my legs when I used to race bicycles, either. I guess I make a lousy acolyte