Handling Device orientation problem for swapped views - cocoa-touch

Question

i'm doing an ipad application, in which i have say two views
mainview and aboutus view
on startup i put the mainview in the rootcontroller's view (the one that is added to the window) alone.
and there's a button on mainview, that, when pressed, will remove the mainview from superview and put the aboutusview instead. aboutus has a similar button that gets us back to mainview.
Now the problem lies in the rotation (orientation).
when i detect an orientation change, i update the displayed view. works fine. (for mainview and aboutusview)
But if i rotate once any view, and then then try to see the second view. it seems that the second view is not autosizing.
CODE in rootViewController:
- (void)viewDidLoad
{
[super viewDidLoad];
_currentOrientation=UIDeviceOrientationPortrait;
[self.view addSubview:_mainView];
[_splashView removeFromSuperview];
}
-(void)viewDidAppear:(BOOL)animated
{
_currentView = _mainView;
}
-(void)toggleMainPage
{
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:.5];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:[self view] cache:YES];
[_infoView removeFromSuperview];
[self.view addSubview:_mainView];
_currentView=_mainView;
[self transformViewAccordingToOrientation:_currentOrientation];
[UIView commitAnimations];
}
-(void)toggleAboutPage
{
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:.5];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:[self view] cache:YES];
[_mainView removeFromSuperview];
[self.view addSubview:_infoView];
_currentView=_infoView;
[self transformViewAccordingToOrientation:_currentOrientation];
[UIView commitAnimations];
}
-(void) transformViewAccordingToOrientation:(UIDeviceOrientation)toInterfaceOrientation
{
if(toInterfaceOrientation == UIDeviceOrientationPortrait)
{
[_mainBtnCustom setBackgroundImage:[UIImage imageNamed:#"main.png"] forState:UIControlStateNormal];
_infoImage.image = [UIImage imageNamed:#"about.png"];
}else
{
[_mainBtnCustom setBackgroundImage:[UIImage imageNamed:#"mainr.png"] forState:UIControlStateNormal];
_infoImage.image = [UIImage imageNamed:#"aboutr.png"];
}
}
- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
[self transformViewAccordingToOrientation:toInterfaceOrientation];
}
- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
_currentOrientation = [UIDevice currentDevice].orientation;
[self transformViewAccordingToOrientation:_currentOrientation];
}
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (_currentOrientation !=interfaceOrientation);
}
what am i doing wrong?