I've created two polymeshes, and each one has its own unique texture. I then merged them into one polymesh, and the scene (working with 4.2) shows that each texture is still applied to the right parts (I.e. it's not trying to just use one texture file to skin the whole thing).

The problem is that when I export this to .xsi to be converted to .msh, I guess it loses its recognition of using both textures. How do I export this so that it uses both and not just one?

Try making the model a single Polymesh first, then apply the textures by selecting each part separately on the single mesh (makes it ahrder to select them ). Apply the textures than export.

I think your problem was that you applied it to 2 separate meshs then merged them.

Bandu's (I think it was his?anyways) tut on applying multiple textures was on doing it to a single polymesh.

I don't suppose that XSI "remembers" the original polymeshes, before they were merged?

EDIT: I suppose it does, which surprised me. I didn't realize it would keep the data as clusters. Whoops. Dumb me.

Well, they SHOULD still be 'attached' to your model - it just don't recognize the 'path' to where the pics are. Sometimes it uses NoIcon to show this, and other times it instead shows nothing but grey.

It's basically all you need to do is to reassign the path to the texture(s) as they are still attached to your Library.

Go in XSI in your Explorer View. Then where it says Scene_root (per default) you click on the scrolldown and selects Images.

In here you have the list of assigned and applied images in your library of your scene. Those not used will be tagged <Not Used> in case you aren't sure of which one you can 'freely' delete

Clicking on the icon of '1' will open the Properties for that selected image. (clicking one of them and pressing Enter works the same way.)

By directing the path to your new path will assign it the texture.. and the polymeshes will still have all of the ones it had before exporting assigned...

I hope this helped