Adding same button to all view controllers in UINavigationController

I have a UINavigationController (to use like a wizard page) which I create programmatically and I need to display a "Cancel" button to cancel the process in any UIViewController.

Creating the UINavigationController:

FirstVC *firstVC = [[[FirstVC alloc] initWithNibName:@"FirstPage" bundle:nil] autorelease];
firstVC.delegate = self;

navigationController = [[UINavigationController alloc] initWithRootViewController:firstVC];
[self.view addSubview:navigationController.view];

Adding Cancel Button:

UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelRequestNewLeave:)];
navigationController.topViewController.navigationItem.rightBarButtonItem = cancelButton;
[cancelButton release];

But when I push a second page to UINavigationController the cancel button is not shown on the UINavigationBar. If I go back to first page, the cancel button is there. So, apparently the button is added only for the first view. I believe this is because I'm not subclassing UINavigationController, because I need to use it in a subview. But I don't know how to set the rightBarButtonItem in a UINavigationController which is created programmatically.

navigationController.topViewController.navigationItem.rightBarButtonItem = cancelButton;

Can someone shed a light on this?

Thanks in advance.