Hello!
I'm the one who is supposed to miss the obvious, the always beginner.

Maybe, it is worth to add some hints in the manual, because their are others who miss the obvious, but who are afraid to confess their dullness.

Please have a look in this thread, it includes a full script to test the vec_for_normal and vec_for_vertex issue that I had:
http://www.opserver.de/ubb7/ubbthreads.php?ubb=showflat&Number=380885&#Post380885

http://www.puppenheim.org/
http://www.wuerfels-welt.de
Old Game Tutorial: http://www.puppenheim.org/MITutorial.zip
Free Game Editor: http://puppenheim.org/AlienalsWeihnachtsmann.zip
http://www.puppenheim.org/blender_starting_main_settings.txt