Hello Community,
There is a LAM (ldap account mananger) plugin for the scalix:
http://www.rg-se.de/scalix/index.htm
"With the plugin for the LDAP Account Mananger users and groups can be administered comfortably centrally in the OpenLDAP directory of the data server. So do you do not have duplicate work because changes on users and groups in OpenLDAP need not be changed on the Scalix server."
For more informations, click on the link