Objective-c – UIButton inside UIView doesn’t respond to touch events

I've put a UIButton inside a custom UIView and the button is not receiving any touch events (it doesn't get into the highlighted state, so my problem is not about being unable to wire up a touch inside up handler). I've tried both putting it into the XIB in Interface Builder, and also tried programatically adding the UIButton into the UIView seperately, both ended with no luck. All my views are inside a UIScrollView, so I first though UIScrollView may be blocking them, so I've also added a button programatically exactly the same way I add my custom view into UIScrollView, and the button worked, elimination the possibility of UIScrollView could be the cause. My View's hiearchy is like this:

The button is over the image view, and the front layer isn't occupying my button completely, so there's no reason for me not be physically interacting with the button. At my custom view's code side, I'm creating my view as such:

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        UIView *sub = [[[NSBundle mainBundle] loadNibNamed:@"ProfileView" owner:self options:nil] objectAtIndex:0];
        [self addSubview:sub];
        [sub setUserInteractionEnabled:YES];
        [self setUserInteractionEnabled:YES];
        CALayer *layer = sub.layer;
        layer.masksToBounds = YES;
        layer.borderWidth = 5.0;
        layer.borderColor = [UIColor whiteColor].CGColor;
        layer.cornerRadius = 30.0;
        /*layer.shadowOffset = CGSizeZero;
        layer.shadowRadius = 20.0;
        layer.shadowColor = [[UIColor blackColor] CGColor];
        layer.shadowOpacity = 0.8;
        */
    }
    return self;
}

I've tried all combinations of setUserInteractionsEnabled, and had no luck. (Yes, also set them to checked in Interface Builder too). I've also read in another question with a similar problem that I should try overriding 'canBecomeFirstResponder' to return 'YES' and I've also done that too. But the problem persists, I can't click the button. I've not given any special properties, settings to the button, it's just a regular one. My other objects in the view (labels below, image view behind the button etc.) are working properly without problems. What could be possibly wrong here?

Thanks,

Can.

UPDATE: Here is a quick reproduction of the problem: https://dl.dropbox.com/u/79632924/Test.zip
Try to run and click the button.