Import script for custom backButton

[signsi]

Hi all!

I've got a small question concerning an import of a snippet.
In my app I want to use a custom backButton.
The code I use is the following:

    UIImage *backImage = [UIImage imageNamed:@"backbutton.png"];
    UIButton *backButton = [UIButton buttonWithType:UIButtonTypeCustom];
    backButton.frame = CGRectMake(0, 0, backImage.size.width, backImage.size.height);
    [backButton setImage:backImage forState:UIControlStateNormal];
    [backButton addTarget:self action:@selector(pushBackButton:) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *backBarButtonItem = [[[UIBarButtonItem alloc] initWithCustomView:backButton] autorelease];
    self.navigationItem.hidesBackButton = YES;
    self.navigationItem.leftBarButtonItem = backBarButtonItem;

It does work when it for example is in the viewDidLoad-Method.
Now I have several views where I do have to use the custom button.
I could copy the code to each view, but I'm sure this would be the poorest solution. How do I import code like this to each file?

Thank you very much in advance

Greetings

signsi