iPhone accessibility with a 'lightbox' effect

My app presents a menu popup with a kind of lightbox effect - the rest of the screen is dimmed by placing a translucent UIView over it, and I add a UIView containing a few menu options. When the user selects a menu item, or dismisse开发者_如何学Pythons it by tapping elsewhere on the screen, the translucent view & the popup menu are removed from view.

I'm struggling to make this accessible. When the popup appears, it's not preventing background elements from gaining focus with VoiceOver, and you have to swipe through every single element on the page before reaching the menu items. Any suggestions on how to handle this?

If you can require iOS 5, set the blackdrop’s accessibilityViewIsModal property to YES.