Okay, I talked to our modeller & config coder. Here is complete answer.
He said that there are two options to overcome this 12 wheels problem;
We chose the first one...
1- Defining the wheels the way DBR_ONIX mentioned, in O2, therefore you don't need a script to turn the wheels. Very smooth...
2- Using a script to turn the wheels. In this case, the wheels are not defined as they are done in the first option, in O2, so they need to be animated via a script to turn.
Hope this fulfills your curiosity