Help with setting my DKIM to sign email from all virtual domains

==== Required information ====
- iRedMail version: 0.8.4
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Linux/BSD distribution name and version: CentOS v6.4 64-bit edition
- Related log if you're reporting an issue:
====

I found an older post talking about this and I made the suggested changes:

1.> added all of my domains to the @local_domains_maps list.
2.> made the one default dkim_key line look like this:
          dkim_key(".", "dkim", "/var/lib/dkim/<my domain>.pem");

My server is still only singing emails with DKIM for the primary local domain. What else am I missing to make DKIM work as a catch-all?