In the hair room, you can highlight the hair growth area (red) like you would to grow hair on the head... BUT instead of growing hair on it, choose "create prop" from the group editor..the red selection will become your new prop.. THEN move the new prop up a tad (y axis), delete roue figure so the new "skullcap' is all thats left, save it in the props folder.. I dunno if this is the right way, but it seems to work