Add Header of DomainKeys status

[N Alaudeen]

Greetings,

Using SpamAssassin 3.2.5 and Exim 4.71.

I want to *add* the status of the DomainKeys in message *header *for
incoming emails, such as "X-DK-Status: pass". (We can see the DomainKeys
Signature on email header.)

Is it possible to add header as mentioned in SpamAssassin by adding module
and configuring accordingly?.

Extract from Header:

*DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=mime-version:date:message-id:subject:from:to:content-type;
        b=F3ALOfOTeWyGdqg2hT33ZtCLeteiYoKxkN2I8pnRPMR0zppZQKYgLfyM2i68UZNBRw

oHdZ6sXXQLREY6sGtivvAYZQxq3PiK3AWY6J7SYwdyBnyPrX6I1th9NshfL1M/OPhjDj
         uAsRwrTJhkDvKMznU1zNjhbsDPJlbOFHN07+o=

*Regards

Alaudeen