[Exim] adding subject header with exiscan and spamassassin

Hi all,

I'm using exim 4.30 with the exiscan patch, along with SpamAssassin
2.60. Works quite well :)

Something I am not clear about is the modification of the Subject:
header. If run from the command line, SA adds a spam-score header, a
spam-report header, a spam-flag header, and if configured, modifies
the subject header by adding a string such as [spam] to it.

However, I can't find a way of doing this with the exiscan patch. What
I *have* found is that by using this configuration:

warn  message = Subject: *SPAM* $h_Subject
      spam = username

I can *add* a second subject line to the message. In mutt, this is not
a problem; it simply displays 2 subject lines. I'm more worried about
users of other (read M$) clients, and how they would deal with 2
subject headers. Or, if they use a filter on the subject header to
delete the spam, how will their filter react to 2 subject headers.

Does anyone have any experience with this that they would like to
share?

--
Anand Buddhdev