I have just configured the LDAP plugin correctly and it works.
It has a bug though: some users are not recognized and phpScheduleIt gives an "Unknown Error" alert whenever I try logging with one of those.
The other users, in the same OU as the non working ones, log in perfectly.
I believe the bug may be their surname ( used in "sn", "cn", "displayName" and "name" attributes ) being two word ( "Di Gangi" and "Di Marco" ).
I'll try debugging and correcting it by myself, just tell me if this may be an issue for LDAp plugin.