Exporting Custom Normals

Hi folks,

I’m trying to update a model exporter script I wrote for blender 2.75 as to consider custom normals created with the “Data Transfer” modifier (applied).

Example: I want the purple normals to export, and as I understand they are based on loops.

http://i.imgur.com/CzPU3IO.jpg

I can import custom normals just fine with

for i in range(0,len(me.vertices)):
    me.vertices[i].normal = normals[i]

I tried accessing the blender normals like

no = me.loops[loop_index].normal

and

no = me.vertices[vertex_index].normal

but both of these only yield the unedited normal.

I read the custom normals are stored in some additional data layer, but I couldn’t find much in the doc or the modifier’s manual page. As far as I can tell the FBX exporter doesn’t export modified normals. Does anyone have an idea or some code snippet?

Cheers