A new patch is available here <ftp://ftp.openldap.org/incoming/pierangelo-masarati-2010-05-26-add-if-not-present.patch>
It includes support for SLAP_MOD_SOFTDEL (see discussion here <http://www.openldap.org/lists/openldap-devel/201005/msg00003.html>). p.
