proxy / email / certificates help

Hi there,

I'm setting up and email server which is reverse proxyied behind a front 
end apache server.


For the same domain...my dns has both a primary web server server, and 
an email server sitting behind a single wan ip.

First question.

Is this possible?

At this point all email is working except smtp, which I'm thinking is a 
certificate problem.


So I have certicates on the email server apache and the apache server 
providing the reverse proxy.

And of course Postfix and Dovecot could have config issues, but mostly 
here I'm looking for verifying my described concept is

achievable using apache.


Comments or links to feasability and tips are always appreciated.

Thanks,

Bret