Robert is correct. 4 screws on the side pieces(don't know their name, maybe windshield posts?), and the center rod. Also, in my case, I loosened the posts from underneath, it's a 17mm socket on a 10mm thread bolt. This makes it much easier to get the thin aluminum frame out.
I've been given incredulous looks because I've removed my windshield about 5 or 6 times. It's not that big of a deal. Don't overtighten any fasteners or tweak the windshield. Don't drop it. And certainly don't let a bolt or a drill bit touch the edge. Then you're good. Just be careful. I usually just grab a beer and sip it slowly while I'm working, it slows everything down just enough to lose the nerves without getting you stupid.
I've no idea how the Vintage Speedster header is made, but the Beck has a steel insert where the latches bolt.