Brake screw... casing.... thing
So I've got a track bike and I'm trying to put a front brake on it, and I happened to have an old ultegra 500 front brake lying around and decided I would just use that, however, the little tube thing that screws into the opposite side of the fork(picture 1) doesn't come on the frame I bought and I can't find the original one, I've got one for the rear brake on another frame of mine(picture 2, I pulled it out all the way so it's sticking out, but you get the idea) but it doesn't really seem to want to come out. Basically, I want to know what this thing is called and whether or not I can get one at the LBS. Thanks
P.S. Sorry about the quality of the pics, my camera phone is pretty fail.