Simply... great!!!
Thank you so much TIG. I am a computer graphics researcher and I am going to use models from the warehouse as testing purposes for my current research topic. As you could have argued, I am not familiar with sketchup and its scripting, I am just using it for file format conversion. The warehouse is, above all, a great testbench, but models with wrong appearance make my tests useless.
So, once again, thank you!
Thank you very much for your quick reply,
but I still have problems with it: the fix reversed plugin says that zero faces have been fixed. re-exporting it produces the same, non textured model.
Any idea?
Thank you very much for your plugin!
Unfortunately, I tested it with some models downloaded form the 3D warehouse, and the resulting OBJ has some texture missing (materials have no map_Kd), although they show fine in sketchup.
Any idea? I attached a small polygon cut from the original model if you want to test
incriminated part of the model cut out
I'd appreciate some insights on it 
Thank You!