Quote - I think you can do it the free version of UVmapper.

I'm not saying the above is wrong, but if it is correct, that's news to me. I would like someone to tell be how to do it in the free UV Mapper.

Poser can't create double sided ploygons. There is a free utility "Objaction TwoFace" that can make an obj two sided. It works on the whole obj though, so if you only want part of it two sided, that part would need to be a separate group so you could split it off from the object, make it two sided, then recombine it with the object. You should be able to find Objaction TwoFace here at Rosity in the Free Stuff.