[exim] exim4 + ldap integration: requirements

Hi all,

i need to integrate exim4 with an openldap 2.2 for virtual domains
(hosting).

Actually i'm serving the same function using exim4 with mysql but i
would like to do it for several reasons from ldap (openldap/slapd).

The OS is Debian Sarge, just to point briefly the environment.

The problem is that i couldn't find good sources to achieve this and the
Exim4 official book don't show this theme extensively.

I would like to know if i need any other schemas than the packaged with
openldap (core, cosine, misc, inetorgperson, corba, java, nis, openldap)

Also i would appreciate is somebody can show me examples.

TIA,
BR,

jonathan