corner radius argument for drawRect()?

[jeff tapper]

has anyone had any luck using the 5th argument (corner radius) of the 
drawRect method of UIObject in flex?

According to the docs:
r - Corner radius of the rectangle or object containing radii for each corner.
I'm seeing identical results if i passing in "0" as I am passing in 
"50000" is this a documentation error, or is it really possible to specify 
a corner radius for drawRect?