I don’t think your problems are related to PrettyFaces at all. It seems more like a problem with the overall interaction between the different components involved in the login process.
One of the key things you should check is the following:
If you invoke an action method and return pretty:someId there, you should definitely be redirected to the target page. If this doesn’t work, you should use Firebug to have a look at the AJAX response you get from the server.
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