UINavigationBar Background Image Problem

Question

i have set my navigationbar background with this code in my App delegate:

@implementation UINavigationBar (UINavigationBarCategory)
- (void)drawRect:(CGRect)rect {
    UIImage *backgroundImage = [UIImage imageNamed: @"Nav-rightpane.png"];

    CGContextDrawImage(UIGraphicsGetCurrentContext(),
                       CGRectMake(0, 0, self.frame.size.width, self.frame.size.height),
                       backgroundImage.CGImage);
}
@end

This works perfect but now i must change the background to the default at UIPopoverController. Any idea for this?

Thanks