Problem with XML Installation

I work with texture maps in my scenes. So different objects have different textures that are present on a texture map.

If I install The file with the XML method the objects don't get the right textures. In my scenery Birds Air Route, for example, there are animated locomotives that have 3 different textures. Installed according to the XML method all get the same texture.
If I install according to the old method over the cfg files the locomotives get the right 3 different textures.

Does anyone have an idea why?