How can you camouflage the bottoms of black rubber boots?

A couple of buddies and myself have created a ghille suit for a school project, and paint balling etc. We were testing out the ghille today and everything is perfect, it totally blends in and breaks up our human outline; Except for one thing.. Our boots stand out, the bottoms of our boots we are wearing are black and there normal black rubber boots. Only the bottom shows and the rest is covered by the ghille. We attempted to paint the bottoms of the boots with extra paint with success in looks but not in the Field, the base still stands out. Any ideas?