[Closed] Envelope end points of biped bone?

Hi,
I’m trying to get the world position of the bone’s envelope end points in Skin modifier.

The way I do it:

skin_mod = $.modifiers[1] --Skin modifier
bone_node = $Bone001 --the only bone in my Skin modifier

envStartPointWorld = (skinops.getStartPoint skin_mod 1) * bone_node.transform
envEndPointWorld = (skinops.getEndPoint skin_mod 1) * bone_node.transform

point pos:(envStartPointWorld)
point pos:(envEndPointWorld)

It works fine in case of BoneGeometry, CATBone etc, but when it comes to Biped it doesn’t work.
When my envelope goes along the longest axis of my Biped_Object bone type the getStartPoint and getEndPoint functions returns vectors of length 1.0, no matter how big the biped bone is. So I guess I need to multiply the returning vector by the length of the bone, but how determine it’s length?