Problem with alpha and retexturing the moon

[lonezergling]

Ok, as lame as it is, I'm trying to retexture the moon into the death star.

 

I have a deathstar moon in Oblivion and I'm going to have on in FO3.

 

My problem lies somewhere dealing with the alpha and .dds format. I'm using Photoshop CS3 but also have GIMP if it's going to work.

 

I've managed to copy-paste-adjust the death star onto the moon to my satisfaction, but when saving it as a DXT1, the moon is surrounded by a big white square, though the death star looks to my liking.

 

Now, if I save it as a DXT5, I can get it so the square is gone but there is still the alpha map from the moon I pasted over, so sometimes the death star has a waning/waxing shadow, which I don't want.

 

Now if I either delete or alter the alpha channel so that it doesn't have that shadow effect, the game fails to load. I can get to the start menu but once it's loading my save, it's CTD's

 

So does anybody have any thoughts/tips/suggestions?