I wanted to subclass UINavigationBar (to set a custom background image & text color) and use that for all the navigation bars in my app. Looking at the API docs for UINaviga
Try creating a [UIColor colorWithPatternImage:(UIImage*)image]
and setting it to the NavBar's backgroundColor property. I haven't tried this yet, but I will do it right now.
I dunno if you got this figured out. But for others that might have this problem...
What you need to do is to specify the class in your XIB to your class name (in this case MyNavigationBar.
Check session 123 in WWDC 2011.
Set the UINavigationBar "tint" property to the color you want.