That sounds difficult... so I've implemented a workaround: I parse the .mtl file myself and add the color for each image with the following code:

    BufferedImage result = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB);
    int cr = color.getRed();
    int cg = color.getGreen();
    int cb = color.getBlue();
    for (int y = 0; y < image.getHeight(); ++y) {
      for (int x = 0; x < image.getWidth(); ++x) {
        int v = image.getRGB(x, y);
        int r = (v >> 16) & 0xFF;
        int g = (v >> 8) & 0xFF;
        int b = (v >> 0) & 0xFF;
        r = r * cr / 255;
        g = g * cg / 255;
        b = b * cb / 255;
        v = ((255 & 0xFF) << 24) | ((r & 0xFF) << 16) | ((g & 0xFF) << 8) | ((b & 0xFF) << 0);
        result.setRGB(x, y, v);
      }
    }

Then I add the image under the name of the mtl-material to the TextureManager, and I create my own transient .mtl file where each texture has the name of the mtl-material and give that to the Loader.

The result looks the same like in poser.

But I think there is a little bug in Loader.createOBJObject, at the moment it is:

tid = tm.getTextureID("mtlName");

if it were

tid = tm.getTextureID(mtlName);

then I wouldn't need to create a transient .mtl file.

It works, thank you very much for this super fast reply 

I'm sorry that we have to use this strange format, but after all it's working best with poser. Ok, poser itself could be considered a bug ;-)

I was very happy to see that the new version of JPCT can import Wavefront .OBJ files. Sadly it doesn't work with files exported from Poser 6 and / or Milkshape 1.7.9 and 1.8.1a. The first file results in an empty object, the other file results in an object that reminds a little bit of a hedgehog - it's very spiky.

You can download the files from this url - it's the same object, one from poser and the other one from milkshape (it's the poser .obj file loaded in milkshape and saved again as .obj with milkshape):

http://b1.world-of-dungeons.de/hose_milk.zip

This is the code I use to load the files:

Object3D[] o = Loader.loadOBJ(filename, filename.replaceAll("\\.obj", "\\.mtl"), 100f);
for (int j = 0; j < o.length; j++) {
  world.addObject(o[j]);     
}
world.buildAllObjects();

Thanks for any help!