[exim] conditin in content-filter

We are using the internal content acl (previous exiscan patch) wuith
exim 4.62

I need a condition to deny SPAM-forwards to foreign providers.
We are signing SPAM messages in the subject line with
    *****SPAM***** ...old subject...

my attempt:

  deny message = SPAM from internal hosts will be denied
       condition = ${if ! eq {$sender_host_name} \
       {\N^(.)*\.(.)*\.uni-magdeburg\.de$\N}{no} \
       {${if match 
{$h_Subject:}{\N^\*\*\*\*\*SPAM\*\*\*\*\*$\N}{yes}{no}}} \
  }

It shall deny connections from hosts with names
    abc.xyz.uni-magdeburg.de
if the subject headers has already *****SPAM*****

(I tested it with my own host (lottmann.urz.uni-magdeburg.de) and a
simulated subject header

    ******SPAM***** test... )

???

MfG M.Lottmann

It doesn't work ... what is wrong