Sorry, Coco, the Hyde brace replaces the threaded collars. It also moves the seal location a couple inches higher on the tube. Here are the mounting instructions in case you don't have them.
http://www.britcycle.com/Manuals/546102AInst.pdf
Also I wonder if it will fit with a CNW front fender?
By this do you mean the reproduction ($35.00) Harley Dyna Glide fender? (Oops, did I let one of Matt's secrets slip?) If that's the one, then I'm sure it will fit.
I plan to use the Hyde brace on my cafe racer when I replace the Dunstall front end with a 12" full floating Brembo 4-pot. I'll try to use my 'glass JPN fender with it.
I am using the chrome version Dyna Glide fender on my Interstate with the 12" Brembo set-up and holding the Hyde brace up to it, it looks like there is plenty of room.