Anybody aware of a helmet lock that will work with the European micro-ratchet chin straps? Since there is no D-ring the standard ones will not work.

If your speaking of the Nolan style latch. I use one of these through the latch, then lock it on the bike. They work great. There are other brands and styles out there!

http://www.whitehorsegear.com/helmet-lock-extension

I bought some substantial "split key-rings" and thread them through the strap. From a distance they look like normal D-rings and I use that to lock the helmets. Won't stop a determined thief, but to most casual observers they look secure.

i set my shoei on the right rearview mirror and hope for the best, so far so good 

i set my shoei on the right rearview mirror and hope for the best, so far so good 

I do that sometimes, but almost always get My mirror sweaty from the cushion in the helmet. I guess I'm a sweaty pig. LOL

standard cable lock through the "facehole" if it's a full-face helmet. I used to carry a long one to lock my jacket and helmet to my Harley.