I found the solution and I will register it here, just in case someone needs it.
I created an UIViewController property to hold my ViewController2. After that, I added the following method:
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
self.vc2.view.frame = self.viewA.bounds;
}