[exim] howto store virtual users in ldap

hello,

i try to store virtual users for different domains inside a ldap
database. this is the first time i use ldap, so please don't wonder
about dump questions ;)

i still did not decide which schema to use, as i don't know which is the
best for my case.

i have to split mail accounts on the system by domain, so
user1@??? is another account than user1@???.

as far as i understand, i need the mailaddress ($local_part@$domain) and
the maildir folder inside the ldap.
exim could put the mail inside the maildir folder depending on the
mailaddress, and a imap/pop3 server could use the same database.

and want to store the mail accounts inside subfolders (organizationalUnit).
i need attributes mailAddress and mailMaildir, but how exactly do i add
entries to ldap?

with qmail.schema i got the following to work, but i guess it's a little
bit overkill for only two needed attributes.

dn: uid=bla@???,dc=resivo,dc=mejo,dc=net
        objectClass: inetOrgPerson
        objectClass: qmailUser
        uid: bla@???
        sn: bla
        cn: bla
        mail: bla@???
        mailMessageStore: /home/mailusers/bla/Maildir

are there any other schemas that cover the two required attributes?

the best would be some example exim4 config and ldif file from somebody
who has virtual users and domains stored inside ldap and uses this for
mail + imap/pop3 servers.

bye
jonas