Consider it a blessing in disguise that the shit knob above does not fit. With that being said check out www.inlinefour.com You can get yourself a pretty decent aftermarket Razo knob for between 24-34 dollars.

http://www.inlinefour.com/razleatspors.html
http://www.inlinefour.com/razowrspec.html

Other than the shiny ones, I only like the baseball type stitched one. Just for the record...