extra button in rightbarbuttonitems not showing - objective-c

Question

I create two UIBarButtonItem in the code below. Later I add them to rightBarButtonItems yet only one of the two buttons shows up (the one I put first on the list).
I thought perhaps that the title's view (which is not set) would be in front of the rightBarButtonItems, since the Apple docs says "If there is not enough room to display all of the items in the array, those that would overlap the title view (if present) or the buttons on the left side of the bar are not displayed."
But that doesn't seem to be it either, since the view's frame = {0,0}{0,0}
I can't figure out what I'm doing wrong. Can anybody tell me how to get all rightBarButtonItems to show? Code:
UIBarButtonItem *shareButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:#selector(shareAction:)];
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setFrame:CGRectMake(0, 0, 30, 30)];
[button setBackgroundImage:[UIImage imageNamed:#"custom-bar-button.png"] forState:UIControlStateNormal];
[button addTarget:self action:#selector(barButtonTapped:) forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *wishlistButton = [[UIBarButtonItem alloc] initWithCustomView:button];
[self.navigationItem setRightBarButtonItems:[[NSArray alloc] initWithObjects:shareButton, wishlistButton, nil]];

Answer 1

Use UIBarButtonItem:
UIBarButtonItem *button = [UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:#"custom-bar-button.png"] style:UIBarButtonItemStylePlain target:self action:#selector(barButtonTapped:)];
instead of:
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setFrame:CGRectMake(0, 0, 30, 30)];
[button setBackgroundImage:[UIImage imageNamed:#"custom-bar-button.png"] forState:UIControlStateNormal];
[button addTarget:self action:#selector(barButtonTapped:) forControlEvents:UIControlEventTouchUpInside];