[exim] ACL to scan From: header is not working

Hi,

Here is my ACL to scan From: header of each message which arrives to my
servers Exim:

  warn !authenticated = *
          condition = ${if
match_domain{${domain:$h_From:}}{+local_domains}{yes}{no}}
          log_message = Spoofed Email
          message = X-Spam-Flag: FROM-SPOOF

I have local_domains list definied at the top of Exim.conf.

This ACL should add "X-Spam-Flag: FROM-SPOOF" extra header to each message,
which was recived by my servers exim, not authenticated, which has "From:"
domain set to any domain included on my local_domains list.

This ACL is not working, I don't know why. Do you have any idea what is
wrong with this ACL?

Mike