je ne sais pas, je ne parle pas francais 
but i'm glad you got it working now 
Ich kann ein bischen (Schweizer-)Deutsch verstehen aber ist es Schmerz im Arch zu lernen !
I hope it's understoodable :lol:
I understood how this bug works and how to make .obj imported from blender have their material. Dunno if it's worth to add this in the wiki or any fix planned ?
well what was the problem?
adding a hint in the wiki is always a good idea, so the others don't stumble upon the same problem.
The bug is: when you import a model from Blender (2.43 here), you attach it to a Node n which is attached to the rootNode, if you apply a MaterialState to n, then all the children of rootNode will be affected (at least for me).
I didn't have the strange idea to apply the MaterialState to all the TriMesh (one by one) directly. In my case it works.
Also I'm still a newbie at Blender but the way I export is more than simple:
-no need to flip the normals (again, Blender 2.43).
-leave all import to default.
-better save your model.blend before exporting.
-export your model JUST AFTER you loaded your UVmap image then export the UVmap.
Normaly in your .obj you should have one (maybe more) line like this:
usemtl Material_yourUVmapFile.tga
s 1
if not, it won't even load the texture nor the material.
I don't have time to understand the "why" :|.