How can a plugin add message-specific headers to an email?

[Alban Deniz]

Hello,

I'm developing a plugin, and need to add message-specific headers to the
email.  Because the headers are different for each message, adding a
"add_header" line in the .cf file isn't what I need.

I did find the put_metadata method, but invoking it in
Mail::SpamAssassin::Plugin::extract_metadata() didn't work.  Here's the
code:

        sub extract_metadata {
        
         my ($self, $opts) = @_;
        
         $opts->{msg}->put_metadata("X-Extract-Metadata", "Test
        header");
        
        }

I was hoping to see the header "X-Extract-Metadata: Test header" in the
email, but that didn't happen.

Is there any way to make that happen?  I looked over the documentation,
other plugins, and developer email lists, but didn't find an answer.
I'd appreciate any help (suggestions, references, etc).

I tried this using the spamassassin command line using SA 3.2 on Fedora
7, and also SA 3.2.4 on Ubuntu 8.0.4.

Thanks,
Alban