I will take a look at this paper. The matter of CP violation is of course interesting, and it is important to understand how this discrete symmetry is violated, presumably at lower energy. I do think that solving the problem of CP violations by breaking the equivalence between inertial mass and gravitational mass is at best converting the problem from one form to another. Think of it from a Gauss law perspective. Consider a large mass M made with matter and a smaller mass made of antimatter m. If I were to put a Gaussian surface around the two of them the gravitation at the surface would be that of a mass M - m. Now force the small mass m into M, and BOOM you are left with a mass M - m in the center and a shell of photons of mass 2m approaching the Gaussian surface. The observer on the Gaussian surface would detect this huge pulse of radiation E = 2m and from gravity would now detect a gravitating mass M - m. Now suppose this Gaussian surface is a perfect mirror that reflects the light back to the mass M - m. The Gaussian surface measure of gravity would then have a mass M m. The interaction between matter and antimatter would increase the amount of gravitational mass.
Solving the CP violation issue with this seems to be a rather odd solution. Of course nature could turn out to be strange. Performing this experiment would be of interest, and I suspect or at least hope that nature does not turn out to be this crazy.
Cheers LC