How to display 2 lines of text for subtitle of MKAnnotation and change the image for the button on the right?

I am looking at Apple's MapCallouts example for map annotations and callouts (==bubbles that appear when you click on a pin). Every annotation there has coordinates, title and subtitle. I would like to display subtitle in 2 lines, i tried with:

- (NSString *)subtitle
{
return @"Founded: June 29, 1776\nSecond line text";
}

but the text "Second line text" stays in one line and makes bubble wider.I get this:

I would also like to change image of the button to one of my own's, the code that sets the button is currently like this:

UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];

Any ideas?

EDIT: I tried 7KV7's advice. Button change is successful, but i still cant get subtitles in 2 lines. My code:

MKPinAnnotationView* customPinView = [[[MKPinAnnotationView alloc]
                                        initWithAnnotation:annotation reuseIdentifier:BridgeAnnotationIdentifier] autorelease];
        customPinView.pinColor = MKPinAnnotationColorPurple;
        customPinView.animatesDrop = YES;


        // Button
        UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
        button.frame = CGRectMake(0, 0, 23, 23);
        button.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
        button.contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;

        //UIEdgeInsets titleInsets = UIEdgeInsetsMake(7.0, -20.0, 7.0, 7.0);
        //button.titleEdgeInsets = titleInsets;

        [button setImage:[UIImage imageNamed:@"ic_phone_default.png"] forState:UIControlStateNormal];
        //[button setImage:[UIImage imageNamed:@"ic_phone_selected.png"] forState:UIControlStateSelected];
        [button setImage:[UIImage imageNamed:@"ic_phone_selected.png"] forState:UIControlStateHighlighted];
        [button addTarg