Why don't you re-edit the movie so there's only one death star the whole time? The Death Star 2 battle could be their first try, from a base on Hoth, while it's still being built, but the Death Star's ground assault pushes them out, and the Millenium Falcon escapes into the Asteroid field, and ESB as per the original film. Then they have to go to Endor to destroy the shield generator after being rescued from Jabba the Hutt and the fleet attacks the completed Death Star while Luke dukes it out with Vader inside...or on Couruscant or wherever...It ruins the idea that Luke blows up the Death Star, but it does kinda fix that admitadley pretty lame premise of there being a SECOND Death Star built. Of course ROTJ was a really cool movie, but I mean come on you know? "Ooops, if at first you don't succeed Vader!!! Try and try again!"
I dunno, another idea