Ignoring unknown parameter "idmap domains"

Dear
according this wiki
http://wiki.samba.org/index.php/Ldapsam_Editposix

i have enable EditPosix extension but i receive this error

Ignoring unknown parameter "idmap domains"

How can i fix it ?

Here it is my smb.conf :

[global]
workgroup = MSHOME
netbios name = PC-DTOUZEAU
server string = %h server
disable netbios =no
syslog = 3
log level = 10
log file = /var/log/samba/log.%m
debug timestamp = yes

# Controler ?? -----------------------------------
security = user
enable privileges = yes
domain master = no
local master = yes
preferred master = no
domain logons = no
os level = 40