Hacking together a model(Not the process just a question)

My personal skins is going to have a beret on his head. Now since I’m adding the beret through 3dsmax, I have one question. Like headhacking, would I edit the qc file, and if so, how would I change it?

You would need to make any edits in the SMD or whatever itself, the QC tells what materials the model uses along with where it should be located.