[Bf-python] What does Armature.EditBone.matrix really does?

[Rodrigo Hernandez]

*Hello,

For an importer I am writing I need to set bones with a matrix, so when 
I create armature bones I use Armature.EditBone.matrix, however, on the 
UI there is no way to set an edit bone matrix or clear rotation or 
scale, all manipulation is done through head tail and roll, which are 
also available through the **Armature.EditBone object.

I was looking at the Blender code, and the EditBone struct doesn't seem 
to even keep a matrix, so I need to know how exactly does the Python 
variable works in order to set it correctly, or switch to using just 
head, tail and roll.

Right now my exporter works halfway, the bones are created, and 
seemingly positioned in the right places by just setting the matrix, but 
no rotation or scale is reflected, however, if I set them to be 
connected, I get errors later on pose bones. What happens to scale and 
rotation set this way? would I be ok, if I only used the matrices to 
determine the position of the heads and assume then all bone matrices 
are set to the identity matrix?

Can someone tell me how do the matrix translates to head,tail,roll? or 
just point me to the file on the Blender source that contains the 
assignment function so I can use its operations in reverse.

Thanks in advance.
*