My suggestion would be to have a bit of a google and I'm sure you'll find plenty of info about further configuration. Keep in mind that TurnKey is Debain under the hood and OpenLDAP is installed from the Debian repos.

If you find anything of value, please post back. Also if you think that there is some specific setting or config that would make the TurnKey OpenLDAP appliance better OOTB then please also share your thoughts on that too...