Attached Link: http://www.soft-rabbit.com/

The filter performs a real "de-emboss" function, resulting in a greyscale template that (somehow) matches the one that was used in the first place. However, it will not (and cannot) re-create the precise original, because Poser's .bum conversion is not "reversably unique" (which means that it is even impossible to re-create the original) and also subject of various rounding errors which make it even more difficult to reverse the process. For that reason, the resulting grayscale will contain a couple of distortions (mainly some gray shades) that typically need some retouching/editing afterwards. If you have a chance to get the original it will be the first choice, but if you can't then the re-conversion is a reasonable alternative. I'm terribly sorry that I can't offer a PC version (yet).