Help with cyrus-imapd, cyrus-sasl, postfix and lmtp

[Dale J Chatham]

my intent it so have postfix in the DMZ delivering to cyrus lmtp and 
cyrus internal.

I'd like to not have to have a map of users, but to use ideally sasldb 
to determine users and passwords, but pam if necessary.  I'd rather use 
stock packages and avoid compiling from scratch.

Distro is centos 6.3

I can't seem to get all the pieces talking to each other and have taken 
a week reading everything I can find.  This would seem to be a natural 
way to run, but I can't find docs on it.

If there is a FAQ out there, someone please point me to it.

TIA,

   Dale