Track keyboard position in iOS 5 with unlocked / split keyboard

I have a view that needs to be exactly on the keyboard, but I am not using a UITextView, so I cannot use inputAccesoryView.

Anyway, before iOS 5 I had no problem, the problem is with the unlocked / split keyboard. Now I have to listen for changes in the keyboard frame with UIKeyboardWillChangeFrameNotification, so I do

[[NSNotificationCenter defaultCenter] addObserver:self
                           selector:@selector(keyFrameChanged:) 
                               name:UIKeyboardWillChangeFrameNotification
                                   object:self.view.window];

      

        
        
        
      

    

So, once the keyboard has been moved, the result is this:

- (void) keyFrameChanged:(NSNotification *)notification
{
    NSDictionary* userInfo = [notification userInfo];  
    CGRect keyboardEndFrame;
    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];

    // Animate view with keyboardEndFrame data
}

      

        
        
        
      

    

The problem is that 99% of the time, UIKeyboardFrameEndUserInfoKey returns null, so I have no clue about the keyboard position.

Thank!

PS: I was able to bind the view as inputAccesoryView by overriding this property in my UIResponder subclass (not read-only anymore), but I still want to know how to keep track of the keyboard frame.