Quote - The xTran and the zTran dials seem to move the prop along the same axis...

This is almost certainly a case of gimbal-lock. It sounds to me like this is the reason the translate dials were hidden, to hide the fact that the props suffer from gimbal-lock.

Quote - The armor is composed of several pieces: some of them are figures (cr2) and some are props (pp2). To load the armor, you must load each piece in a precise order, set its parent to another previously loaded piece or to M4 himself (not conforming them), then repeat for each piece.

I can't for the life of me imagine why it needs to be as complicated as it sounds from your description. I don't have the "An Armor Clad Warrior", so perhaps it is unfair of me to comment on something I have never seen, but perhaps this is just a very poorly constructed piece of clothing, that should never have made it on to the market.

My advice would be. Give the vendor a fair chance to resolve the issues, but if he can't, ask for your money back.