diff -u -r1.7 -r1.8
--- OverlayDriver.java	29 Apr 2011 20:01:34 -0000	1.7
+++ OverlayDriver.java	30 Apr 2011 04:44:38 -0000	1.8
@@ -589,7 +589,9 @@

 		int status = mcParticle.getGeneratorStatus();
 		double time = mcParticle.getProductionTime();
 		BaseMCParticle copyMcP = new BaseMCParticle(origin, p, ptype, status, time);

+		// override the mass and charge from the particle type to prevent unknown particle exceptions

 		copyMcP.setMass(mcParticle.getMass());

+		copyMcP.setCharge(mcParticle.getCharge());

 		copyMcP.setSimulatorStatus(mcParticle.getSimulatorStatus().getValue());
 		return copyMcP;
 	}