iphone4 camera flip button not working when using overlay

Question

Hi, I'm setting the UIImagePickerController's cameraOverlayView to a view that I created so that it simply overlays an image when someone is using the camera. This works fine. The problem is that on the iPhone 4 there are two buttons: one for flash and the other to flip to the front facing camera. These buttons no longer work. I'm assuming because my overlay view is above them, but I don't know how to resolve this.

Any help would be greatly appreciated, thanks!!

Here's my snippet of code if needed:

OverlayView *overlay = [[OverlayView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];

UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;

picker.sourceType = UIImagePickerControllerSourceTypeCamera;

// Insert the overlay:
picker.cameraOverlayView = overlay;    

[self presentModalViewController:picker    animated:YES];
[picker release];