You can convert default splines created by the XGen geometry instancer to interactive grooming hairs. After converting the splines, you can use the interactive grooming tools to sculpt the hair or modifiers to add effects. Guides from a default splines description do not get converted with the splines.
Maya does the following:
To modify the hair using the interactive grooming tools, you need to add a Sculpt modifier to the description. You can also add other interactive groom modifiers to shape and control the hair.