Its strange because I maked a new texture for the pants of "the Girl" and put it in de pose directory and that worked out fine.  i can apply it to the base model pants.

In the faq : "Is there a Macintosh version of MAT Pose Edit?
Unfortunately no. But if you have Pro Pack or P5 you can use a Python script for making MAT files."

Well I have P7 and don't know what a Pro Pack is?