Trying to add a UIButtonTypeRoundedRect to an annotation view. Everything shows up fine (title and subtitle), and there's space to the right of the details where you'd expect the button to be, but the actual button itself never shows up. Any ideas?

UIButtonTypeRoundedRectInAnnotationView

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation {
    MKPinAnnotationView *annotationView = nil;
    if(annotation != mapView.userLocation) {
        static NSString *reuseId = @"annotationView";
        annotationView = (MKPinAnnotationView *)[mapView dequeueReusableAnnotationViewWithIdentifier:reuseId];

        if(!annotationView) {
            annotationView = [[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:reuseId];
        }

        annotationView.canShowCallout = YES;
        UIButton *infoButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
        infoButton.frame = CGRectMake(0, 0, 22, 22);
        annotationView.rightCalloutAccessoryView = infoButton;
    }

    return annotationView;
}