[exim] Some DKIM Clarifications

Right now I'm using: "dkim_verify_signers =
$sender_address_domain:$dkim_signers" to trigger the DKIM ACL. That
should cause it to be called for any envelope sender, regardless of the
header signatures, right?

So I can easily check things like: "dkim_status = invalid" or
"dkim_status = fail" in the ACL. But what about the case of:
"dkim_status = none"? I have sender_domains checking a domainlist of
senders I know always use DKIM, but what I'd like to have access to is
if the domain has published a public key, and always sign, then make use
of the "none" status in that case.

Is there an easy way to return a true for domains with public keys
indicating that they sign all messages?

--
Chris