Problem with approx research and wildcards

Hi,

I'm trying to use the aproximate search like this: #ldapsearch (title~=toto)

it's ok, but when I use some wildcards I have an error like this: #ldapsearch (title~=toto*)

ldapsearch: ldap_search_ext: Bad search filter (-7)

I don't understand why.

in my slapd.conf, I think i have a goog thing: moduleload back_bdb index title eq,pres,sub,appr

and I use an debian with openldap stable:

# slapd -V @(#) $OpenLDAP: slapd 2.3.30 (Mar 9 2007 05:43:02) $ root@windlord:/tmp/buildd/openldap2.3-2.3.30 /debian/build/servers/slapd

Thanks in advance, if you have a response for my problem

Regards,

Xavier