I'm sure you already tried this, but... did you check the face dot product against a control value which pointed in a known direction, and all that?  I seem to recall your thread on the topic.  Do you have the link to it handy?  Now I'm curious....

===========================sigline======================================================

Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.