Red Shadow campaign

[Egosz]

Has anybody finished the Battle of Chita map yet?
I found the turn limit too less for three stars, because of these things:
1. You can conquer town of Chita in turn 6, then 5 heavy bombers come from the East and a lot of heavy tanks come from the West supporting by a huge amount of infantries.
2. You have nothing against planes so you need at least 2 AA guns what means 2x2=4 turns.
3. Against heavy tanks and many infantry units you need a heavy bomber as well what means another 8 turns.
4. It's 18 turns all together, so you can make only two actions with that heavy bomber around the town of Chita, while the last town centre is on the far West.
5. I don't know if it is because the machine gun, heavy machine gun and mortar changes or not, however, AI Japan cannot support the invasion effectively. Our only plane belongs to Japan, but AI uses it for kamikaze attack for the first possible occasion.

Has anybody an idea how to solve this map in the required 20 turns? Thank you in advance!