I'd love to get the Pinlock, but they don't make one for the Scorpion EXO-900 that I can find, and I'm reluctant to home-mod my fancy helmet :P
Pinlock used to sell a "do it yourself kit" , but only in Europe. I think US liability laws have made them not import them. (Although according to their web site they are still getting alot of requests for one)
Really, it shouldn't be too hard to adapt one made for another helmet to work with one not on the list. The price of trying would only be the cost of two visors. (Or one for the helmet and a cheap one to cut up.)
I had once made something simular for an open face helmet by just siliconing a cut down visor on top of another. I may try this with one of my other helmets over the winter and post some photos if it works out.
If you have ever seen how the Pinlock system works, you would understand why I say it really shouldn't be that hard to do. All you are attempting to accomplish is to build a "double pane" window for your helmet, buy standing off a smaller sheet of plastic from the main one inside the helmet with a soft rubber seal around its edge to create a dead airspace between them.
The "pins" just hold the inner shield on by the outer edges...just like putting a playing card between your thumb and forefinger and causing it to bend slightly. So the real key is the placement of those pins so they let the inner visor follow the contour of the helmets standard visor. (You slightly flatten the main visor to install the smaller inner one)
Goggles don't keep your face warm, and you'd be letting in more cold air in without the helmets normal visor there.
I'm surprised someone here in the US has not come up with a copy of the Pinlock system that works on any helmet yet...........