Yes, there currently isn't a way to add additional skin selections to the setup. The reason being is three things that come off the top of my head. 1st is the 3D model itself, which is preset to accept the skins that are in the cdds file. 2nd, the .exe file (don't muck with it, it will become instantly unusable) has the skin names going to that 3D model. 3rd, the .exe file references the CLSID number that's in the MeInit.xml file. You can change the names of the selections (Like from "1st Squad KIAP" to something like "My Personal skin") but, backup the MeInit.xml file (found in Lock On\ME folder) and edit to some degree. As for 3D editing tools? Yeah, okay.....
And thanks Serval, as I was going to do what you did