You can actually make a skullcap for any figure using Poser's grouping tool. Select the parts of the head mesh you want for the skullcap in the grouping tool and then spawn a prop from it :). You can then make the groups you want on the resulting skullcap in the same fashion. Please keep in mind tho that the denser the mesh you are growing hair on, the denser the hair will be, so if you do create your own skullcap you might want to take it into a modeler and subdivide it once. You can even create your groups in the modeler if it's easier for you.

Laurie