I have no idea what they actually used for that metallic looking stuff. It looks almost like mylar. But I've decided to try this:
1) Cut out pattern piece on silver (or a better color if you can find it) lamé.
2) Spray glue the back of the pattern piece (be careful to remember which is the back when you glue it; the glue will easily bleed through to the front, too)
3) Glue the piece to some bottomweight fabric (I'm using white--I don't think it matters much).
4) Spray glue the bottomweight fabric to very thin batting.
5) Stitch some straight lines across the pattern piece, to give it the lined texture.
6) Fabric-spray-paint the lamé to the right color if it's not right already.