Autocad .dxf export

Hi Blenderartists !

trying to export a blender scene to .dxf format, I fear something goes wrong with the module, or I misunderstand some optional features. The thing is I would like to separate several objects in distinct dxf LAYERS. For the time being, i.e. calling the exporter with default settings, the whole set of objects within my scene goes in a single layer named PYDXF.

I tried to play around with the available options :

entitylayer_from=..., layerName_from=...

but I can’t get anything but a single layered file.

Do you know what I do wrong ? is it a known issue of this export tool ?
Thanks for your replies.