Not able to handle UIInterfaceOrientationPortraitUpsideDown for view Controller for iPad

In my iPad app i have tabbarController for firstView, for tabbarController i added button when we press that, one viewcontro开发者_StackOverflow中文版ller will come. My problem is when i am trying to turn that viewcontroller in PortraitUpsideDown, it was not comming to PortraitUpsideDown. The code i use in that viewController is

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Overriden to allow any orientation.
return(interfaceOrientation == UIInterfaceOrientationPortrait || interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown);

// return YES; }

}

Can anyone tell me that What mistake i made or anything is there to add. Thank u.