[exim] Migrating from qmail to exim question

Hello everyone,

1st of all thanks for taking the time to read and reply to my inquiry here.

I am very in-experienced when it comes to mail server administration,
however I was assigned a task to migrate an existing qmail server running
on a ubuntu 8.0 server to a new opensource mail server that will be
install and setup on a fresh redhat enterprise version 6 server.

doing a bit of research I came across exim and it seems a really good MTA
choice for our purpose specially being open source. ( we can't afford to
have any commercial products )

Is there any good documentation out there that can help me, guide me
through migrating 300 mail boxes from qmail server to exim server? our
current qmail server uses the Maildir format and we would like to keep the
new one that way, also runs courier-imap for IMAP on ports 143 & 993, we
don't use POP3, and all users in qmail server authenticate to their e-mail
accounts through an openldap server that is hosted on the qmail server as
well. Our current qmail server does not have any aliases setup nor virtual
domains.

One option I was looking at for IMAP service on the new server is dovecot.

I would like to test this procedure on a VM that I have setup but am
planning on deploying to a production environment in the next 2 weeks.

Any help would be greatly appreciate it.