MKMapView with additional UI elements

Question

I want to create a mapping application for iOS that will show a map (MKMapView) and some UI elements (UIButton,...) on top of the map.

Is it a good idea to add the additional UI elements as subviews of the MKMapView or should I create a parent UIView that contains the map and other elements at the same level?

I created in IB a MKMapView with a child UIButton and I can't see the button. However If I grab a reference to the button (IBOutlet) and add it to the mapView in viewDidLoad(), then I see it... but, is it a good idea after all?

Thank you!