sono2000, unfortunately LOD feature is useful only for procedural planets, it doesn't change the appearance of solar system objects which are using textures as elevation maps. Here you can find a PDF with more specific descriptions of what are the sources for each texture pak and relative resolutions.
This limitation could change in future, but it doesn't appear to be a priority according the TODO list.
Edit:
HD and Ultra addons will be repacked anyway for Steam version, according SpaceEngineer.








