Odd error with toolbar resizing when view pushed onto navigation stack

Question

I have a drill down application with a detail view containing a scroll view which has a number of text fields, etc, and a table view. I have added a toolbar which which appears above the keyboard (including animating in and out with the keyboard in the keyboards show/hide methods).
The problem is that, while the keyboard toolbar appears fine normally, when I push a new view controller onto the navigation controller stack (by selecting one of the cells in the table view), the keyboard toolbar visibly warps to fill the whole screen as the new view is sliding in.
Furthermore, when I go back to the previous view, the keyboard no longer has the toolbar above it, even though the size/position of the keyboard is the same as before in the keyboardWillShow method.
I am getting the frame rect for the keyboard toolbar as follows:
UIWindow* mainWindow = [UIApplication sharedApplication].keyWindow;
UIView* mainView = self.view.superview;
NSTimeInterval animationDuration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
keyboardFrameRect = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
keyboardFrameRect = [mainWindow convertRect:keyboardFrameRect toView:mainView];
Where self.view is the scroll view (I am using the scroll view's parent view to make sure the tab bar is calculated independently of the scroll view's scroll).
I'm not sure if this is a common problem, or if I'm trying to do something that you're not supposed to, so if anybody has any advice I'd be grateful.

Answer 1

this question has been resolved by an apple tech support guy and as such I am closing this question and marking it as answered.