EDIT: Hm the link to the “Character Studio SDK” in that thread seems to be broken.
I just read that the studio has been directly integrated into 3ds max some time now, so I think this one is the most recent SDK stuff: http://usa.autodesk.com/adsk/servlet/item?siteID=123112&id=7481368
A BIPED SDK function call “BipIface->RemoveNonUniformScale(1)” that may be inserted into any existing MAX exporter. (see also bipexp.h, located in the cstudio\docs folder)
Werner