LDAP authentication with special char in password doesn't work

When trying to connect to OpenERP (with LDAP module installed) it doesn't works if password contains special chars (at least é char). For every other "simple char password", no problems.

Here is the server error log :

OpenERP Server Error
Client Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/http.py", line 195, in dispatch
    response["result"] = method(self, **self.params)
  File "/opt/openerp/server/openerp/addons/web/controllers/main.py", line 817, in authenticate
    req.session.authenticate(db, login, password, env)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 116, in authenticate
    uid = self.proxy('common').authenticate(db, login, password, env)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 31, in proxy_method
    result = self.session.send(self.service_name, method, *args)
  File "/opt/openerp/server/openerp/addons/web/session.py", line 104, in send
    raise xmlrpclib.Fault(openerp.tools.ustr(e), formatted_info)

Server Traceback (most recent call last):
  File "/opt/openerp/server/openerp/addons/web/session.py", line 90, in send
    return openerp.netsvc.dispatch_rpc(service_name, method, args)
  File "/usr/lib/pymodules/python2.7/openerp/netsvc.py", line 293, in dispatch_rpc
    result = ExportService.getService(service_name).dispatch(method, params)
  File "/usr/lib/pymodules/python2.7/openerp/service/web_services.py", line 433, in dispatch
    return fn(*params)
  File "/usr/lib/pymodules/python2.7/openerp/service/web_services.py", line 445, in exp_authenticate
    return res_users.authenticate(db, login, password, user_agent_env)
  File "/opt/openerp/server/openerp/addons/base/res/res_users.py", line 421, in authenticate
    uid = self.login(db, login, password)
  File "/opt/openerp/server/openerp/addons/auth_ldap/users_ldap.py", line 252, in login
    entry = ldap_obj.authenticate(conf, login, password)
  File "/opt/openerp/server/openerp/addons/auth_ldap/users_ldap.py", line 105, in authenticate
    conn.simple_bind_s(dn, password)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 206, in simple_bind_s
    msgid = self.simple_bind(who,cred,serverctrls,clientctrls)
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 200, in simple_bind
    return self._ldap_call(self._l.simple_bind,who,cred,EncodeControlTuples(serverctrls),EncodeControlTuples(clientctrls))
  File "/usr/lib/python2.7/dist-packages/ldap/ldapobject.py", line 96, in _ldap_call
    result = func(*args,**kwargs)
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe9' in position 4: ordinal not in range(128)