You have to find all of the TextureStages on the model. Each TextureStage can have a different texture. If you apply only a texture with the one-parameter setTexture() call, you have only replaced the default TextureStage, without changing the others.
The code you paste above is a very clumsy way to find all of the TextureStages. An easier way is to use model.findAllTextureStages().
Read up about multitexture in the manual to learn more about the way TextureStages work.
David