At first glance it looks like there would be a small bar that the wing's 4 posts are hooked around. I made a close inspection as I moved the wing up and down...and noticed that there is actually no small bar. There is what looks like a good sized bar running the length of the body.
That being said I just took my handy dandy X-Acto knife and just shaved off all the excess paint that was built up in all the post slots. I worked the wings up and down to see where they were rubbing. Then shaved lightly continuing to move the wings inbetween shaving til they would move into and lock in a correct down position.
Knowing that the bar inside the body of the shuttle for each wing is a decent size I am not as scared as when I got them to move the wings up and down. So with a little patience, and a good sharp knife you can get them wings a working too!