On this page, there is a download that contains a mesh of a male wearing a shirt but no pants.  But it is a single mesh, so it can't be interchanged with another shirt.  I've tried using Milkshape to split that and various other meshes (such as underwear meshes) into two parts so that I could get what I want, but it always results in an empty mesh appearing in the game, so either it is not possible to do this or I'm doing something wrong (despite following the tutorial at this page as best I can).  And this web board doesn't seem to allow private messages, so I can't contact the creators of the meshes directly.  So I am posting this here to see if anyone can help me.  I would be looking for male and female adults and teens if possible. I don't necessarily want a nude mesh, because I am going to combine them with long shirts that will cover up the crotch area anyway.  So underwear would be just as good and maybe a little bit better looking.  I am aware of the various problems with texture bleeding and underclothes sticking out of overclothes and that doesn't really bother me.

Thank you for you attention and help.