You'll need both 3DS Max
2009 (I can't stress the "2009" enough -- 2010 seems to have a few flaws with importing the rigging) and
BrawlBox v0.65c.
First, open the character's PAC files (I'll use Luigi for this), and export the model as a DAE file somewhere (right-click the "FitLuigi00" file with the "MDL0" tag to the left of it and choose "Export", or by pressing CTRL+E on it).
Import the DAE into 3DS Max using the Autodesk DAE (which should be the default anyway, so don't worry about that), and make sure that the root bone (TopN) has a scale of "100.0". If it isn't, re-import it and change the scale to "Centimeters" or whatever, which shouldn't scale it down to 0.3937 (why it does that by default, I may never know). Now, it should be wo--GNRGRGRAGH
Sorry, just kinda creeped me out a bit. Luigi's only using his upper eyelid textures, which due to the transparency (and the fact that they're hidden) just sees through his head. Let's change that to his pupil textures.
Hm. That doesn't look right. That's because it's still using his eyelid's UV mapping channel instead the pupils, which is what it's supposed to use. Now, if you go to the Diffuse properties for the material, and change the "Map Channel" to 3...
Yeaaaaaah, that's how it's supposed to look. But that's not how you fix it, so don't do it that way, and change it back to the first channel. First, check in BrawlBox for the materials which have multiple UV channels. For this, it would be the eyes.
That tells you which textures to use with which layers. Now, back to 3DS Max. Duplicate the offending polygon groups by the amount of layers (so for 4 for each eye for Luigi). Whatever's on top will
not need to be fixed, as it's already using the proper UV channel... Now here's the important part -- click on the hammer tab on the top-right to get to the Utilities tab, then click on the "More..." button, and click on "Channel Info". After doing that, a new button should be at the bottom of the tab, click on that to get to this:
Now, for the material that uses the second layer (in this case, Luigi's lower eyelids), right-click on the second UV mapping channel (2:map / UVSet1) and click on "Copy". Then click on the first one (1:map / UVSet0) and paste. If done correctly, the UV mapping on the object itself should change.
And then do so for the other layers, copying the third and fourth channels respectively over to the first channel.
(And skip to the pupils for the before-and-after, because obviously there's gonna be nothing visible for the eyelids.)
And it should look like this when it's completely done and everything's in working order:
I just did a simple UV mapping translation to show the eyelids are visible/working. And of course, you might have to modify the mesh a bit to to fix the material layering... Either way, that's how you would go about fixing the UV mapping for those characters with multiple UV mapping channels per polygon.
Either way, the model should be good to export after that. Unless you're like me and you want to make sure the smoothing groups are proper between polygon groups.
((I think I explained it enough...
))