(And Susano? How did Westphalia end CRER? I know it didn't start it, but surely part of the whole "Westphalian nation-state" thingy is the ability to determine your own religion...)
Nope. Westphalia geographcially fixed religion. States were not allowed to change it anymore. The princes were still able to convert themselves, and to dictate the religion of their household (meaning in the Princes case the palace including staff), the best example being the Saxon electors, but the territories religions was firmly fixed by the treaty, and was not allowed to change anymore in order to prevent further religious conflicts. Hence, during negotiations a day was picked as fix date, and how religions were distributed that day was used as base. Since as said counterreformation marched on during the war, what date that should be was atcually a major dividing point during the negotiations. In the end the Protestants were successful in that part of Counterreformation was rolled back by the treaty.
Its kinda perverse. Those people literally thought the other side would end in hell for praying teh wrong way, and then they so cynically went about that. It was necessary though, and perversely, it did help. Over time, most of thelarger states included territories of both denominations, and couldnt change them! (Withe xceptions - Sweden and France were the tereatys guarantee powers, and hence when France dictated that the Palatinate be catholiced by force at the end of the War of the Great Alliance, that did happen - and neither the Catholic rulers nor Habsburg had any problems with that of course). Hence, states in Germany began to be religiously tolerant, in some cases from the end of the war on. (Which really makes the "South Germany forms own state because of own culture!" threads so ridicolous).
But yes, that way Westphalia ended ERCR after 93 years (established at teh Augsburg Religious Peace of 1555).
I think he wants a religion map, not a states map
/E: Sorry about the img-tags...