Mission editing has never allowed us to put eastern units on the western side in the editors, but I believe in this game, with the way it uses changeable camo, you should be able to Wear the camouflage of either side. I understand why you wouldn't want this, it would lead to some issues with players identifying friendlies as enemies, which would lead to more tk'ing.
But that's part of this game, you can get into an enemy vehicle and drive it around, why not make yourself look like one of them completely. It only makes sense.
It also adds in another idea for the future, infiltration. To be able to infiltrate an enemy base by looking like one of them. If your wearing some sort of face protection and otherwise full gear, they won't be able to tell your not friendly unless they talk to you.