I started thinking more about this subject in the WSC in Berlin. Before it I was just jumping in the model and now getting some difficulties (think I´m the only one that can go deep on my models).
I found with one colleague the technique IDEF-SIM http://www.informs-sim.org/wsc11papers/138.pdf, which I intend to apply to my models.
Agree that Simio could facilitate model conceptualization.
Eduardo.