Pierangelo,
I don't want to get into a debate about the importance ofdocumentation, but documentation is really one of the most important things about software. If you as a developer understand the code, this doesn't mean the code is usable since most of those who use it are not developers and do not know how to read the code. Everybody appreciates the time and effort given by the developers. The administrator guide has no mention of the overlays (at least not chain) and the man pages do not give enough description, also the administrator guide could add examples for some configurations, maybe like those ones being asked in the mailing list.
Oh please, stop bitching and moaning about the documentation! I can't take it anymore on this list. Why don't you go to work and send in documentation improvements? I'm not a developer but I fully agree with them. If you want better documentation, send your improvements to ITS or to the FAQ. As a good LDAP admin you can figure out how it works.
kk++
+1 from me.