IIRC, in addition to the hidden selection part in the config, you need to have made a part for the model in O2, which is then defined in the hidden selection. For example, you create a small flat area in O2 and place it where you want to have the texture. You then need to name that part to whatever you wish, and define it as arm, leg, head... depending on the place where you placed the part. Get me?
So in short, it's not just the config. For examples, you can look at the BAS Ranger models and see how they did it, or I can send you one of my soldiers so you can see how it's done.
I hope this cleared the thing up a bit. If you have any more questions, post here.