If it continues to build up a lot, it means the yeast is still alive. You can knock them out with gelatin, sorbate, and sulfite, if you want it to end quicker. Are you sure fermentation was done before kegging? EDIT: Looks like maybe that answer is no. Sorbate will severely injure the yeast. I see you already added gelatin and Campden. Now try sorbate. Maybe that's the kick the yeast really needs to knock it out. Otherwise them buggers want to keep on causing trouble for you, since you might have kegged just a few days too soon.