Custom UIPopoverBackgroundView: no drop shadow - ios

Question

I've used this good tutorial to create a custom UIPopoverBackgroundView class.
It works well. The only problem is that I am not getting the typical UIPopoverController drop shadow and I want it. I've tried specifying it on the layer of my UIPopoverBackgroundView instance without success. My instance of UIPopoverController doesn't seem to have a public view to manipulate. Adding it to the popover content also doesn't work.
Probably really simple: how do I add a drop shadow when using a custom UIPopoverBackgroundView class?
// UIPopoverBackgroundView.m
-(id)initWithFrame:(CGRect)frame{
if (self = [super initWithFrame:frame]) {
_borderImageView = [[UIImageView alloc] initWithImage:[[UIImage imageNamed:#"bg-popover.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(CAP_INSET,CAP_INSET,CAP_INSET,CAP_INSET)]];
_arrowView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"bg-popover-arrow.png"]];
[self addSubview:_borderImageView];
[self addSubview:_arrowView];
self.layer.shadowOffset = CGSizeMake(50, 50);
self.layer.shadowColor = [[UIColor blackColor] CGColor];
}
return self;
}

Answer 1

You don't need to add your own shadows. The base UIPopoverBackgroundView will do it for you. Just make sure to call super in your layoutSubviews implementation.
EDIT: My comment applies to apps targeting iOS 6.

Answer 2

Ok, figured it out. I needed to add the drop shadow to the borderImageView, not the view of the popover instance.
- (id)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
_borderImageView = [[UIImageView alloc] initWithImage:[[UIImage imageNamed:#"bg-popover.png"] resizableImageWithCapInsets:UIEdgeInsetsMake(CAP_INSET,CAP_INSET,CAP_INSET,CAP_INSET)]];
_arrowView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"bg-popover-arrow.png"]];
[self addSubview:_borderImageView];
[self addSubview:_arrowView];
_borderImageView.layer.cornerRadius = 5.0f;
_borderImageView.layer.masksToBounds = NO;
_borderImageView.layer.borderWidth = 1.0f;
_borderImageView.layer.borderColor = [UIColor blackColor].CGColor;
_borderImageView.layer.shadowColor = [UIColor blackColor].CGColor;
_borderImageView.layer.shadowOpacity = 0.8;
_borderImageView.layer.shadowRadius = 50;
_borderImageView.layer.shadowOffset = CGSizeMake(-10.0f, 10.0f);
}
return self;
}