I would not worry too much on how your new series will be called in the west. From what you have so far has still gained a lot of press. Did you get to see any of the ads that were on the Discovery Channel when Pacific Fighters came out? It was perfect because the Dogfight series was very popular as well. I was in a Squadron who was being split apart due to the fact that people were saying that FB was far better than CFS2. The old guard did not want to give up the Pacific theater of Operations and others wanted your "New" sim.
So when these started to appear
http://il2-sturmovik.de.ubi.com/en/videos.php
That was the ticket to at least 15 more sales because it was based on the PTO. The same can be said for the Battle of Britain. I think as long as you get the message out that it is a new series and not just a new game then that will be your hook. Our word of mouth will help as well. I always called Forgotten Battles by that name, PF by its name. The big plus was when I found out I could put FB + AEP and PF together. The shorter the name is easier to be conveyed in stores and on forums. Just look at why fighter jocks have nicknames. It is easier to reference in the air than Lt.JG John Q. Puplic. So "Cash Money" is a nickname everybody would know. PS. keep this in mind when thinking of all new theaters and maps please. WWII was epic and every nation who fought wants to be represented. Hey today is Veterens day here. S! all.