I can’t really explain but the graphist who’s making the models found another way to export models into a xml format. It’s not exactly OgreXML but it must be pretty similar: I think it’s Ogre ASCII. this way to export allow me to only load the xml (and the models are textured straight). I don’t know if it’s the most common way to do it but it suits me so…
Yes, you can use the default blender material in jme for simple textured models as you said, but the most features are in jme materials (j3m).