I have a BD bike with the carbon fork that is apparently the same as the Nashbar one. When my buddy gave me the frameset, one of the canti studs was out of the fork and the plate came off. The plate with the 3 holes is just held in place by a weak adhesive as mentioned above.

I just put the stud back into place using some threadlocker and positioning the plate and it has been fine ever since. I don't use those Avid brakes so I can't comment on the brake arm specific issue.