Setting a UIImage to a UIBarButton item - iphone

Question

I can't seem to add an image to this UIBarButtonItem without it crashing when touched:
UIBarButtonItem *backButton = [[UIBarButtonItem alloc] initWithTitle:#"Back"
style:UIBarButtonItemStylePlain target:nil action:nil];
self.navigationItem.backBarButtonItem = backButton;
[backButton release];
this code adds an image, but it crashes when touched because of an incompatible pointer types assigning to UIBarButtonItem * from UIButton:
//Setup Custom Button
UIButton *button = [[UIButton alloc] init];
button.frame = CGRectMake(0,0,44,44);
// [button addTarget:self action:#selector(showInfo) forControlEvents:UIControlEventTouchUpInside];
self.navigationItem.backBarButtonItem = button;
[button setBackgroundImage:imgIcon forState:UIControlStateNormal];
self.navigationItem.leftBarButtonItem = [[[UIBarButtonItem alloc] initWithCustomView:button] autorelease];
[button release];
thanks for any help

Answer 1

To call
self.navigationItem.leftBarButtonItem = [CustomBarButton createNavBackBarButtonItemWithTitle:NSLocalizedString(#"Back", #"") target:self action:#selector(actionBack:)];
CustomBarButton has createNavBackBarButtonItemWithTitle class function
+(UIBarButtonItem *)createNavBackBarButtonItemWithTitle:(NSString *)t target:(id)tgt action:(SEL)a
{
UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
// Since the buttons can be any width we use a thin image with a stretchable center point
UIImage *buttonImage = [[UIImage imageNamed:#"back_button_up.png"] stretchableImageWithLeftCapWidth:5 topCapHeight:0];
UIImage *buttonPressedImage = [[UIImage imageNamed:#"back_button_over.png"] stretchableImageWithLeftCapWidth:5 topCapHeight:0];
[[button titleLabel] setFont:[UIFont boldSystemFontOfSize:12.0]];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
[button setTitleColor:[UIColor blackColor] forState:UIControlStateHighlighted];
//[[button titleLabel] setShadowOffset:CGSizeMake(0.0, 1.0)];
CGRect buttonFrame = [button frame];
buttonFrame.size.width = [t sizeWithFont:[UIFont boldSystemFontOfSize:12.0]].width + 24.0;
buttonFrame.size.height = buttonImage.size.height;
[button setFrame:buttonFrame];
[button setBackgroundImage:buttonImage forState:UIControlStateNormal];
[button setBackgroundImage:buttonPressedImage forState:UIControlStateHighlighted];
[button setTitle:[NSString stringWithFormat:#" %#",t] forState:UIControlStateNormal];
[button addTarget:tgt action:a forControlEvents:UIControlEventTouchUpInside];
UIBarButtonItem *buttonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
return [buttonItem autorelease];
}

Answer 2

You have to set the buttonStyle to custom not a UIBarButtonItemStylePlain
and then [barbuttonitem setCustomView:anImageView];