Your Challenge is, that with a PoD not before May 8, 1945, you have the Soviet puppets of Eastern Europe, Poland, Czechoslovakia, Romania, Hungary, etc., unite in some sort of Federation. The capital can be anywhere, and the name can be anything. It must be more centralised than, for example, the North German Confederation, but it still can be a very loose union.
Bonus if you include East Germany (Berlin not a must)
Super Bonus if you include East Austria (Vienna not a must)
You win the challenge with super extra bonus cookie points if you have the federation survive the inevitable fall of communism, become at least half way democratic, and grow to be a Great European Power.
Any takers?