Change items in navigation bar on device rotation

I have custom UIBarButton items added to UINavigationBar as rightbaritems. I add two more items in UIBarButton when device goes to landscape mode. I am getting rotation call and I am correctly removing items from UIBarbuttons array, but my navigationbar item set never gets updates.

I am not sure how I can change navigationbaritems on device rotation. Per me I am doing all things correct.

-(void)setUpOnRotation:(BOOL)toPortrait{

_searchMessage = [[UILabel alloc] initWithFrame:CGRectMake(3.0, 0, 110, 20)];
_searchMessage.numberOfLines = 2;
_searchMessage.textColor = [UIColor blackColor];
_searchMessage.font = [UIFont systemFontOfSize:8.0];
_searchMessage.text = @"";

_searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 15, 130, 25)];
_searchBar.delegate = self;
_searchBar.showsCancelButton = NO;
UIBarButtonItem* doneButton = [BarButtons doneButtonWithTarget:self action:@selector(cancel)];
UIBarButtonItem *searchActivityItem = [[UIBarButtonItem alloc] initWithCustomView:_searchMessage];
UIBarButtonItem *searchItem = [[UIBarButtonItem alloc] initWithCustomView:_searchBar];
UIBarButtonItem *in = [BarButtons nativeButtonNamed:@"In"
                                                  title:@"In"
                                                  target:self
                                                  action:@selector(In)];
UIBarButtonItem *out = [BarButtons nativeButtonNamed:@"Out"
                                                  title:@"Out"
                                                  target:self
                                                  action:@selector(Out)];


NSMutableArray *itemsSet;
itemsSet = [NSMutableArray arrayWithObjects:in,
            out,
            searchItem,
            searchActivityItem,
            doneButton, nil];
if (toPortrait) {
    if ([itemsSet containsObject:searchItem] || [itemsSet containsObject:searchActivityItem]) {
        [itemsSet removeObject:searchActivityItem];
        [itemsSet removeObject:searchItem];
    }
}


[_searchBar release];
[searchItem release];
[_searchActivity release];
[_searchMessage release];
[searchActivityView release];


self.navigationItem.rightBarButtonItems = itemsSet;

}

Note: setUpOnRotaion method is called from willAnimateRotationToInterfaceOrientation and viewWillAppear with UIInterfaceOrientationIsPortrait(self.intefaceOrientaion) and it does give me correct result. I have debugged.