Need quick Help, How to install PITA roof bars

[aerocustoms.com]

I just purchased a 2004 H2 loaded up with everything except roof bars , I just purchased new ones but I can not figure out how to remove those plastic pieces at rear of truck to get access to install the bars, it is pissing me off I even took the rear lights off looking for a way to get the whole rear strip off, I see a torx screw thru the small hole in strip but it holds the track not the bracket looking piece, I pryed hard on it with that cheesewiz clip depressed but it seemed like any more force I would break it in half. Any ideas or pic's would be awesome or direct me to installation link.