[exim] Domain Keys

Hi,

Is there a standard way people are setting up Exim to do domain key
signing on outbound emails?

You need to prepend a header to the entire message that contains a
digital signature. I have the code to calculate the signature. I'm
just curious about the best way to insert it into the header above all
the other headers. The normal system filter header commands insert
headers after all the other headers.

-Vance