I made mine the same way. As far as attaching it, I kind of cheated because I didn't want to drill a bunch of holes in my helm. Instead, I took a couple of 1 1/2 washers and bent them over about 20 degrees and then attached them to the upper edge inside the hem with J&B Liquiweld. Bend the washers over just enough so they sit fairly flush to the helm, but you can still thread the ties of your liner through the holes.