If you are doing this for Poser "only" then it is very easy and does not involve any UVmapping.
Say you want your face on M3 - good: all you need is the texture of the "MilMan" (within the Poser Runtime), something like PS or Gimp (two extremes
), and a foto of your face.
Load up the texture of M3, load the pic of your face, and then clone the foto in place.
Start with the eyes, nose, mouth, and then work out the rest of the skinny parts.
When you are ready, save off the new made texture by using THE SAME PATH but another name (one that you can remember).
Within Poser again and M3 loaded go to the material room and load in the new texture (hoping that you have remembered the name).
Bingo: you on M3 without UVmapper or any other kind of torture.
PS: these textures are really large - but: they have to be, so do not alter the size!