Jabberd2 using MySQL storage and OpenLDAP authentication
If you have any problems at all, the official [Jabberd2 documentation] is superb!
Build Jabberd2 with MySQL and OpenLDAP Support
Copy the official arch build from /var/abs/extra/daemons/jabberd. Edit the PKGBUILD and add mysql and ldap support. Dont delete the SRC directory after your done, you'll need the mysql script in there to populate your initial database.
The manual above walks you through the install of Jabberd very well. Make sure your ids are the same and look to /var/log/errors.log and /var/log/everything.log for help if you get stuck.