I do not remember all the details for what is still outstanding and needing work, other than I know for certain that the sky textures for New Horizons need to be redone for all weather hours, because the old engine format is not compatible. For now, there is only one set of sky textures that the engine will default to, because it won't be able to find the properly named textures in the actual weather hour for New Horizons.
But the modders for New Horizons developed many special sky conditions and textures for various weather conditions, so you won't be able to see their intended sky effects unless similar skybox textures are made to match their intended look.
The newer Storm 2.8 method for the skybox textures requires this:
RESOURCE\Textures\WEATHER\SKIES\xx
sky_BK.tga.tx
sky_FR.tga.tx
sky_LF.tga.tx
sky_RT.tga.tx
sky_up.tga.tx
The older Storm 2.0 look like this, and they can't work:
sky_side.tga.tx
sky_up.tga.tx
I'm sure there are other elements that might still need work, but since I have never played New Horizons, nor have I tested it (other than to launch and verify it works, or when I helped troubleshoot specific problems that either Pillat or pedrwyth gave me saves), I don't know what those might be.
You can find the two discussions here:
http://www.piratesahoy.net/threads/new-horizons-in-maelstorm-2-8.32957/
http://www.piratesahoy.net/threads/new-horizons-on-jlb-maelstrom-2-8-2-engine.28...