Help with understanding qmail-ldap

[BsD JuNkiE]

when setting up an Qmail-LDAP MTA does the actual LDAP server/s have to
be installed on the MTA/s or just the LDAP server libaries?  I am reading how to do this
and the docs. are showing the ldap server/s on a different standalone machine but the instructions on setting it up says OpenLdap needs to be installed before compiling the qmail-ldap MTA code. I thought the whole purpose of using an LDAP solution was to have a central database of users and if the LDAP server/s has to be present on every MTA then its not very central....but i am probably misunderstanding the documentation. What i am needing to accomplish is to have a email system where the MTA /s "only one for now but maybe a backup/s in the future" stores incoming mail for   [EMAIL PROTECTED] . I want the messages to be stored on the MTA or a network attached drive without actually having to have a local user accounts on the MTA boxen. I was wanting to setup another box providing IMAP/POP access to the users accounts on the MTA for retrieval and another box for webmail access VIA apache+mod+ssl W/SquirrelMail.


                    
                            |-------Ldap1-server
                            |-------Ldap2-server
                            |                                                                  
                            |-----------------------------------------------|
                            |                                |                                 |Aapche+SSL                             
                            |                                |IMAP/POP                   Webmail
                  Qmail-LDAP MTA-1
                            |
                            |
                  Qmail-LDAP MTA-2
                            

What i need is to have the Qmail MTA store incoming messages to
[EMAIL PROTECTED]  somehow to a /maildir and i assume it stores it on
the MTA or do i have to setup another server for this? Now i don't want
to have to run to the MTA machine and create a local user account
every time i need to add a user, so can i somehow add the user to the
database and have the MTA create a maildir automatically. I guess what i dont
understand is how to do this without local accounts being present on
the MTA machine. Our team is trying to build a email system for about 1000
users currently and should scale to meet a anticipated 3000 in the future...this is
why i was wanting the LDAP solution.

So far i have downloaded the qmail-1.03 and qmail-ldap patch, patched the qmail code and installed openssl.
I have removed Sendmail, and was going to run make for qmail but i saw the documentation said Ldap must be installed
and thats what i wanted to ask about. Also being a newbie to qmail is there any special config options that you guys recommend
before i run build.

thanks in advance for any help, as i surly appreciate it.

Have a fantastic evening.