Handmaiden's robes are produced by her, and I believe there is a bug that allows her to produce 3 sets, I have gotten two before.
After your half naked training sessions, put your armor or robes back on and ask her to put some clothes back on. She will then say that she fails to see the point and you can say something about training whithout clothes makes you weaker and she will agree and says she has "bulkier" clothes. Viola, magically she pulls her mother's jedi robe out of her arse. I believe if you do this after each training session you will get 3 "handmaiden's robes" items.