FPD simulation - Beam Remnant?

Previously, I did some study regarding the origin of the FPD pi0s in Pythia v6.2 vs v6.4. 

http://drupal.star.bnl.gov/STAR/blog/leun/2010/jan/25/origin-forward-pi0

The attached slides largely repeate this previous exercise for Pythia v. 6.222, but it is proably a bit more coherent.