Maybe you could use, if you have 3DMax, the unofficial exporter, then convert it to something Maya can read, and use that? Its a bit circumvent, but I can't think of anything else right now...

No. I need access to the mesh, because I can bake the texture from one mesh to the original then, but without the correct UV I can't do that. I don't have any problem editing the dds files, that's simple enough in Photoshop with the nVidia plugin, editing the textures isn't an issue. In Maya I can paint both 2d textures, and 3d structures to an object, which can influence the final baked texture on the original object in really cool ways. Making an enormous crater on a planet, or simply painting city lights to a curve attached to the objects skin would be simple enough for example.

The current map for the planets is cross shaped, which leads to less distortion at the poles, but it's not easy to paint to without the exact UV available.

I don't have 3d studio (I stopped using it long ago, when Maya came out), though unfortuneatly both are owned by Autodesk now. If I can get the original meshes in obj format, then I'm set. Later on I plan on bringing ships into the game, and I'll have to use XSI for part of that, but for now I want to start with something simpler. Adding a few new planets would be a good place for that.