I've have 2 seperated folders for normal skins and custom skins replace naked girls. If you want custom skins to replace
naked skins go download either gtainside.com or gtaall.com or even libertycity.net to replace them, don't matter if you want to 
place male or female. I highly recommended to put these skins you download to modloader :D

Just rename the custom skin to gangrl2 or gangrl1 - example

rename to these:
gangrl2
gangrl1
gungrl2
gungrl1
copgrl2
copgrl1
crogrl2
crogrl1
mecgrl2
mecgrl1
nurgrl2
nurgrl1