I may be out on a skinny limb here but here's what I have done in the past....There is a carpet tool for success. It's a carpet hook knife that allows you to get under the lip of the deck (sitting on the floor) to cut and remove the 1/2" - 1" of carpet (under the lip) and make room for the new. Lift the deck lip up with a wide-face pry bar, just enough to cut under the lip and later lay in a new piece and conceal the edge (and secure from ravel). You can raise other areas with a bottle jack where allowed (passenger seat areas where you lift with the jack on the upper part of the deck and allow room for the lip to raise more easily) to lift more edging and a little breathing room. Pretty much a done deal. It's not hard, just a bit time consuming and tedious. Remove your current carpet as much in one piece as possible to use as a template to cut the new.
$0.02 no guarantees...