Could you also have a detailed look which version of PrettyFaces you are using for this example? The problem you described (setter called after navigator call) is a known problem of PrettyFaces 3.3.0. But this should not happen (as described earlier in this thread) with the most recent snapshot prettyfaces-jsf2-3.3.1-20110919.063144-23.jar.
Do you play Magic?
Get TopDecked MTG, the #1 Magic App, built by players, for players. Free to use, forever.