Interface Builder wont let me rename the "View" class name to existing Class

Question

FYI: Im following a tutorial from the book "Beginning iPhone Development", chapter 12.

Here is the setup, i have a two files in the Classes folders called QuartzFunView.m and QuartzFunView.h (ie. a class called QuartzFunView).

Now if i double click on my blaViewController.xib file, then click on "View" and in the Identity Inspector try to change the Class (Class identity) from UIView to QuartzFunView, my computer just beeps and stays as UIView. I can change the class to all the UI.. classes and any other random letter combination i choose, just not QuartzFunView. What am i doing wrong?

Thanks