[Dovecot] SSL only for external connections

Hi

I'm running dovecot 1:1.2.15-7 and php webmail application is throwing errors when connecting to IMAP with TLS. Is there away to disable SSL/TLS for localhost connections? I googled, but didn't see anything specific. Can I assume that it's as simple as setting ssl_listen = to the external IP address(es) and leaving listen = * as it is?

Thanks.

Simon