Arrow on popViewController not going where I tell it

Arrow on popViewController not going where I tell it

I have a UIPickerController that appears when you click a button though
the arrow on it doesn't change position from the bottom even when I use
UIPopoverArrowDirectionUp.
- (IBAction)addPicture:(id)sender {
CGRect rect = CGRectMake(0,650,768,1024);
[popOverController presentPopoverFromRect:rect inView:self.view
permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
}
I guess this must be quite common
Thanks in advance