Pb création boite aux lettres cyrus

Bonjour,

J'ai installé un serveur de messagerie sous Linux (RedHat EL5), avec Postfix, Cyrus-Imap et une authentification LDAP.
Tout fonctionne correctement pour des comptes "standards", cependant, il m'est impossible de créer une boite aux lettres avec un utilisateur comportant une apostrophe dans son nom :-(

L'erreur retournée dans les logs
--------------------------------------
Oct 31 13:04:08 srv-test imap[501]: login: smtp.toto.fr [192.168.1.1] andre.n'goma plaintext User logged in
Oct 31 13:04:08 srv-test imap[501]: autocreateinbox: autocreate inbox for user andre.n'goma was called
Oct 31 13:04:08 srv-test imap[501]: autocreateinbox: User andre.n'goma, INBOX failed. Invalid mailbox name

Mon fichier main.cf
----------------------
queue_directory = /var/spool/postfix
delay_warning_time = 1
command_directory = /usr/sbin
daemon_directory = /usr/libexec/postfix
mail_owner = postfix
myhostname = smtp.toto.fr
mydomain = toto.fr
masquerade_domains = toto.fr
myorigin = $masquerade_domains
inet_interfaces = 192.168.1.1
proxy_interfaces = 192.168.1.1
mydestination = $myhostname, localhost.$mydomain, localhost
unknown_local_recipient_reject_code = 550
mynetworks_style = class
relay_domains = toto.fr
transport_maps = hash:/etc/postfix/transport
virtual_alias_maps = ldap:/etc/postfix/postfix-ldap.cf
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
message_size_limit = 8388608
mail_spool_directory = /var/spool/mail
cyrus_destination_recipient_limit = 1
mailbox_command = /some/where/procmail -a "$EXTENSION"
smtpd_banner = $myhostname ESMTP $mail_name
debug_peer_level = 2
debugger_command =
PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin
xxgdb $daemon_directory/$process_name $process_id & sleep 5
sendmail_path = /usr/sbin/sendmail.postfix
newaliases_path = /usr/bin/newaliases.postfix
mailq_path = /usr/bin/mailq.postfix
setgid_group = postdrop
html_directory = no
manpage_directory = /usr/share/man
sample_directory = /usr/share/doc/postfix-2.3.3/samples
readme_directory = /usr/share/doc/postfix-2.3.3/README_FILES

Mon fichier cyrus.conf
--------------------------
# standard standalone server implementation

START {
# do not delete this entry!
recover cmd="ctl_cyrusdb -r"

# this is only necessary if using idled for IMAP IDLE
idled cmd="idled"
}

# UNIX sockets start with a slash and are put into /var/lib/imap/sockets
SERVICES {
# add or remove based on preferences
imap cmd="imapd" listen="192.168.1.1:imap" prefork=5
# imaps cmd="imapd -s" listen="imaps" prefork=1
pop3 cmd="pop3d" listen="192.168.1.1:pop3" prefork=3
# pop3s cmd="pop3d -s" listen="pop3s" prefork=1
# sieve cmd="timsieved" listen="sieve" prefork=0
lmtpunix cmd="lmtpd" listen="/var/lib/imap/socket/lmtp" prefork=1

# this is only necessary if using notifications
# notify cmd="notifyd" listen="/var/lib/imap/socket/notify" proto="udp" prefork=1
}

EVENTS {
# this is required
checkpoint cmd="ctl_cyrusdb -c" period=30

# this is only necessary if using duplicate delivery suppression,
# Sieve or NNTP
delprune cmd="cyr_expire -E 3" at=0400

# this is only necessary if caching TLS sessions
tlsprune cmd="tls_prune" at=0400
}

Mon fichier imapd.conf
---------------------------
configdirectory: /var/lib/imap
partition-default: /var/spool/imap
admins: cyrus
#sievedir: /var/lib/imap/sieve
#sendmail: /usr/sbin/sendmail
hashimapspool: true
sasl_pwcheck_method: saslauthd
sasl_mech_list: PLAIN
tls_cert_file: /etc/pki/cyrus-imapd/cyrus-imapd.pem
tls_key_file: /etc/pki/cyrus-imapd/cyrus-imapd.pem
tls_ca_file: /etc/pki/tls/certs/ca-bundle.crt
sieveuserhomedir: yes
autocreate_sieve_script: /etc/default_sieve_script
unixhierarchysep: 1
munge8bit: 0
altnamespace: yes
autocreatequota: 153600

Un ldapsearch d'un utilisateur qui me pose probleme
--------------------------------------------------------------
# extended LDIF
#
# LDAPv3
# base <> with scope subtree
# filter: uid=andre.n'goma
# requesting: ALL
#

# andre.n'goma, users, toto.fr
dn: uid=andre.n'goma,dmdName=users,dc=toto,dc=fr
objectClass: top
objectClass: person
objectClass: organizationalPerson
objectClass: inetOrgPerson
objectClass: userSecurityInformation
objectClass: otherContactInformation
objectClass: posixAccount
objectClass: qmailUser
uid: andre.n'goma
cn: N'GOMA Andre
sn: N'GOMA
givenName: Andre
displayName: N'GOMA Andre
userPassword:: cGFzc3dvcmQ=
ou: TEST
description: TEST
uidNumber: 1003
gidNumber: 513
homeDirectory: /home/andre.n'goma
loginShell: /bin/false
mail: andre.n'goma@toto.fr
mailMessageStore: /var/spool/vmail/andre.n'goma
mailQuota: 5242880S, 50C
accountStatus: active

# search result
search: 2
result: 0 Success

# numResponses: 2
# numEntries: 1

Si quelqu'un a la solution, je suis preneur, sachant que je ne peux pas modifier mon architecture, ni installer un autre logiciel pour ma messagerie...