How to add right button on UINavigationbar in UITabbar

Question

I have a problem when add a right button on uinavigationbar. My Nib organizer like this:

CustomTabViewController :UIViewController

-->CustomTableViewController1 : UIViewController

-->CustomTableViewController2 : UIViewController

CustomTabViewControllers are in Tabbar items

I need to save the inputs, I can add navigation item from Navigation Controller, but I can't add them from View Controller when they are childs in Tabbar items. here is my code:

@interface CustomTabViewController : UIViewController <UITabBarDelegate> {
     NSArray *detailViews;
    IBOutlet UITabBar *tabBar;
    IBOutlet UITabBarItem *tabBarItem1;
    IBOutlet UITabBarItem *tabBarItem2;
    UIViewController *selectedViewController;

}

@property (nonatomic, retain) NSArray *detailViews;
@property (nonatomic, retain) IBOutlet UITabBar *tabBar;
@property (nonatomic, retain) IBOutlet UITabBarItem *tabBarItem1;
@property (nonatomic, retain) IBOutlet UITabBarItem *tabBarItem2;
@property (nonatomic, retain) UIViewController *selectedViewController;
@end

@implementation TabViewController

@synthesize detailViews;
@synthesize tabBar;
@synthesize tabBarItem1;
@synthesize tabBarItem2;
@synthesize selectedViewController;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil number:(NSString *)num{

    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {

        // Custom initialization
    CustomTableViewController1 *tVC1 = [[CustomTableViewController1 alloc]initWithNibName:@"CustomTableViewController1" bundle:nil];        
        CustomTableViewController2 *tVC2 = [[CustomTableViewController2 alloc]initWithNibName:@"CustomTableViewController2" bundle:nil];


        NSDictionary *detail = [[[Services sharedInstance] getDetail:num] copy];

        [tVC1 setDetail:detail];     
        [tVC2 setDetail:detail];
    NSArray *array = [[NSArray alloc] initWithObjects:tVC1, tVC2, nil];
    self.detailViews = array;
    [self.view addSubview:tVC1.view];
    self.selectedViewController = tVC1;

        [array release];
    [TVC release];
    [TVC release];       
        [detail autorelease];

    }
    return self;
}
// ....
- (void)tabBar:(UITabBar *)tabBar didSelectItem:(UITabBarItem *)item
{
    if (item == tabBarItem1) {

        CustomTableViewController1 *tVC1 = [detailViews objectAtIndex:0];
        [self.selectedViewController.view removeFromSuperview];
        [self.view addSubview:tVC1.view];
        self.selectedViewController = tVC1;

    } else if (item == tabBarItem2) {
        CustomTableViewController2 *tVC2 = [detailViews objectAtIndex:1];
        [self.selectedViewController.view removeFromSuperview];
        [self.view addSubview:tVC2.view];
        self.selectedViewController = tVC2;
    }
}
@end

the Custom Table View Controllers are inside the tab bars with some default value which need to be change by user and save. I can add a right button on uinavigationbar from my TabViewController class but it can not rich the information inside CustomTableViewController in tab bars. Is there any way to add a right button on uinavigationbar from Custom Table View Controller which I have? Can you show me the solution?