I don't understand your issue.
If you install OFP GOTY, and play as an Eastern soldier, all your AI buddies have Russian voices. You will have whatever voice you've chosen in the player settings.
If you create a mission, you can assign voices to everyone you want in the mission by using identities in the description.ext file. I put in specific Russian voices for both the player and his AI buddies on all my player-as-eastern missions. It works fine.
What version of OFP do you have?