Well the trick is to use a UIButton with an image:
Code:
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
[button setImage:[UIImage imageNamed:@"RefreshIcon.png"] forState:UIControlStateNormal];
[button setImage:[UIImage imageNamed:@"RefreshIcon.png"] forState:UIControlStateHighlighted];
button.imageEdgeInsets = UIEdgeInsetsMake(0, -16, 0, 0);
[button addTarget:self action:@selector(refresh:) forControlEvents:UIControlEventTouchUpInside];
addressBar.rightView = button;
addressBar.rightViewMode = UITextFieldViewModeAlways;