Anthony,
The skirt's probably just a glued piece of white fabric. Most "softgoods" skirts are just that. Some are sewn, but I'm wagering this one isn't. It'd be easy to pop into the fabric store and get a piece of white knit (a yard would skirt up an army) if you wanted. It'd be real easy to fix that if you've got skirtless guys needing fixin'.
I'm probably going to custom a couple as they seem to have different cuts in the movie, actually. It'll add a little variety I think.