HAH! I figured it out!
*dramatic pause*
The secret is Taina's Replacer:
http://www.lucasforums.com/showpost.php?p=2656073&postcount=22)
Screenie of 303nar:
http://i714.photobucket.com/albums/ww150/ajkfjaioIIl9Wkk/303nar.jpg)
Procedure:
1) Followed Taina's instructions
2) When I had the model (303narb) open in GMAX, I converted the "sky" object to editable mesh/re-applied the Aurora Trimesh modifier AFTER I uvmapped. It had no texture when I imported it, so I had to create a new one.
I don't really know how critical the trimesh modifier is, but I decided to be safe and put it back EXACTLY the way I found it after re-mapping.
It reverted back to the original texture, so I had to replace nar_sky1.tga with the texture I wanted from Telos. The mapping seems to have transferred, though.