I have to say - this howto is worth nothing.

A lot more precise is contained in Ubuntu documentation (a month ago was a draft, but steps were described well).

Unfortunately, Debian and Ubuntu versions of OpenLDAP package are compiled against GnuTLS which code is considered unsecure. Google for "GnuTLS considered harmful" to get more details.

The other thing about OpenLDAP GnuTLS based is that it is unable to handle high security protocols only. Using OpenLDAP debug functionality, we will get few errors which IRC support  proposes to solve by recompilation against OpenSSL.

Valuable howto about Ubuntu's OpenLDAP package would be:

1) how to compile OpenLDAP against OpenSSL instead of GnuTLS

2) how to configure it

3) how to configure TLS

4) how to configure address book for Thunderbird