Did you already try with this?
rwm-drop-unrequested-attrs no
If you look through the messages (http://www.openldap.org/its/index.cgi?findid=7673), you will see that the same suggestion was made by Pierangelo Masarati 6 months ago in followup 5. My response in followup 6 was that it doesn't work. A quick test indicates that it still does not work in 2.4.39.
-- Russell Mosemann, Ph.D. Professor of Computer Science