I never used DCS commander since I wasn't worried about the bells and whistles. If he's using a straight DC power pack, he can at least run the engine with the basic chuff and smoke without the DCS commander.
I assumed that if the original poster was willing to gut the engine to get it to run on DC then he's not as concerned about the sound since that all goes away if it is gutted.
If considering the DCS commander to control the whistle and bells then it might be worth giving MTH a call on that one.