Peterbilt BOC/BOS CB Antenna Mount

[AgLaw]

Anyone have experience with Peterbilt's Back-of-Cab/Back-of-Sleeper CB antenna mount option? I ordered it on a new 389 w/a 48" flattop. I was trying to keep the antenna away from trees and such along residential streets that have posed the problem of broken antennas in the past. Problem is, I can't get a ground plane. It seems the bracket (located at the roof cap seam, centered above the back window) is totally isolated from the sleeper body. In fact, it was painted and I had to sand to bare metal to check for continuity. I can get continuity on the bracket itself, but not to other items such as the frame or stainless grab handles. I've seen others with the same Wilson 2000 trucker-series and the BOC/BOS option, but have never been able to talk to them. Am I supposed to be using a no-ground plane antenna? Peterbilt reps say it should work with a standard antenna. However, how can a standard antenna work with a painted bracket--there would be no ground? The factory must be totally clueless!!! That or I am.

I don't have a special radio...just a factory Cobra 29, but I do want it to work! I've thought about removing the sleeper interior for access and drilling the hucks to remove the factory bracket; replacing it with a fabricated stainless bracket that would be re-hucked with stainless hucks. Before I did that, I wanted to seek some other advice. Any ideas?

Thanks.