Checking Domain Keys Inbound, anyone?

[am.lists]

Config:

Postfix 2.2.2, MailScanner 4.55, SpamAssassin 3.15.  Sendmail is
installed and available (8.13.7) but not running as the inbound
listener for mail, PF is.

Would like to add DKFilter for checking the validity of inbound mail
that is signed.

In my first round of research, I can't find any references to anyone
else doing this, and I'm sure that's not consistent with reality. (or
is it?)

For DKFilter, there's a laundry list of perl modules to install. I
have that pre-requisite work done. I just need to know how to piece it
together such that MailScanner can score it.

Thanks,
Angelo