Parking Brake Cable Grommet

[bkaul]

So, I've been hearing an annoying rattle from the right rear whenever I hit a bump, and then after a recent heavy rain, I noticed that my passenger side floorboard was soaked. It turns out the grommet through which the passenger side parking brake cable passes is missing - it used to pop loose, and I'd pop it back in when I noticed. Apparently sometime recently it fell out entirely. Should be an easy fix, if I could find the part, but no one seems to sell it.

Does anyone know where I could find one of these grommets to replace the missing one?

Thanks!