iOS7: Translucent Toolbar in Translucent Navigation Group not rendering correctly

When adding a Toolbar to a Window Navigation (win.rightNavButton = toolbar), the translucent effects are layering and rendering incorrectly - see the attached screenshot.

As far as I know the Toolbar added to the Window navigation bar is the correct way to have multiple icons in the top nav. This method is used by the native apps like Mail / Safari etc.

Is there another method I should be using?

If not, can this be fixed so that the Toolbar when translucent renders correctly on top of the the already translucent navigation bar.