Well, here are what the cubemaps look like..
That purple one is the one being used in the screenshot i posted above, so there's obviously still some diffuse yellow/brown color being applied to the visor somewhere in the shader.. You might do better if you track those values down.
So, now for how I did what I did - quck-n-dirty.. For this, I'm assuming you know
how to find a bitmap's raw data (and I'm just dealing with the main detail level).
Given:
Each face of the cubemap is 64x64
The raw's size is 16896 bytes
The raw's format is DXT1
DXT1s're compressed to 1/2 a byte for each pixel
So I opened Photoshop and made a new image 64x528.. Then saved it as a DXT1 (no mipmaps). Why 528?
16896 / 0.5 / 64 = 528
Then I copied the raw out of the .map, and pasted it into the .dds.. The header's 128 bytes, so leave the first 128 bytes alone and replace the rest. So then I opened the .dds back up in Photoshop and had something that looked like this (but without the watermark

):
So after I Color Balanced it with Photoshop, I saved the .dds again.. I opened it back up with Hex Workshop and lopped off the (128 byte) header, then pasted the rest over the bitmap's raw data in the map.
And that's it.. There's actually some padding between the faces that
should be zero'd out when you replace the raw.. I'd fixed it but I'm assuming it won't make a difference if you don't do it.. Meh.
♫♪ Fantastic! ♫♪