I've been tooling with helmets lately, and have come across the problem of hairstyles showing up if I don't make the helmet large enough to compensate and hide it. I've looked around at other files and not noticed anything unusual or different to what I'm currently doing. There's gotta be something I'm missing here, right? Has anyone worked out how to effectively hide hair that touches the helmets full transparency boundaries?
Make use of the mask.png file, use files from a premade helmet so you can position the stuff properly. Anything white in the file will not hide hair, anything transparent WILL hide hair. I think thats how it works.