If you could find the sky file for Land 2, you could try renaming it and copying it over the regular sky file. That should work. Just make sure to save a copy of whatever you're overwriting, so if it doesn't work you can revert back to the original.
I know that won't work because the atmosphere file type for land 2 is a ".dds" which you can not open using the lighting mod in the landscape editor. Thanks anyway.