I know it would be easier to label each unit on the board as a specific minis unit and just have it out on the minis board, but it would be impossible to keep track of with so many units on the board.
Therefore it would have to be each unit gives you a set, predetermined amount of points that you can spend in the fight.
For example, Japanese tanks in minis suck, so they give you only 20 points each in the minis game to spend on Japanese tanks. So with 5 tanks in a battle, Japan would be able to spend 100 points on tanks in whatever land battle.
Conversly, German tanks were awesome, German tanks give you 35 points each to spend on tanks. That way you could have 2 Panthers or 1 Tiger in the fight.
Planes would have to have differnt costs if they happen to be fightin over land or sea, due to the points differences between land minis and War At Sea.
Of course objectives would have to be eliminated in the minis games and all units would have to fight it out till dead or the attacker retreats, which would require him or her to run all thier forces off thier own side of the minis map.
Oh, and you’ld have to spend a fortune to get enough minis to even try and play the epic battles that happen in the '40 game.