You can´t cheat in DCG in the way you are trying to do. Every vehicle you add to a map, is considered to be owned by the map (ie a neutral force) and not by you, or the enemy.
The only things that is transfered over to the next map, is vehicles that were owned by you from start of the battle, or owned by the enemy AI and later captured by you.
Vehicles belonging to the map, wont be transfered over no matter how many times you try to add it to the map.
Sorry...
~Zeke.