Just want to say to all, if you are from Germany.
This tutorial is useless, because the ckeckbox appears on cart, but not on the last step of checkout.
I spend some hours to realize that I'am working on cart-template and this file is not the checkout page, on which I test it and refresh it like idiot.
Ckeckout page appears if the buyer clicks "buy now" button and goes thru many pages with forms.
And according to german laws this checkbox muss be near of the "complete order" button on the last step.