Setting up LDAP--not seeing overlay debug info

Hi folks,

I am trying to set up LDAP authentication from an Active Directory
server, using the setup from here: It installs OK, but it
never seems to go into the library, from what I can tell.
The docs seem slightly out of synch with the actual code in terms of how
the DEBUG flag is used. I have that turned on (as far as I can tell) but
there is no info. in the logs that matches with the DEBUG output lines
in the code. How do I actually turn on debugging with RT3 and this code?