objective-c - Presenting modal view controller from another presented modal view controller

Question

I have a presented view controller that will then present another view controller. The second view controller does not make views beneath it transparent or disable any below views controls. Has anybody ran into this and how were you able to fix it??

//view controller for invalid username/password popup
IncorrectPasswordViewController *viewController = [[IncorrectPasswordViewController alloc] init];
viewController.view.layer.borderColor = [UIColor whiteColor].CGColor;
viewController.view.layer.borderWidth = 3.0f;

//push the modal on the screen
viewController.modalPresentationStyle = UIModalPresentationFormSheet;
[self presentViewController:viewController animated:YES completion: nil];
CGRect r = CGRectMake(self.view.bounds.size.width/2 - 150,
                      self.view.bounds.size.height/2 - 70,
                      300, 140);
r = [self.view convertRect:r toView:viewController.view.superview.superview];
viewController.view.superview.frame = r;