[exim] Problem with Rexexp in Substitution

headers_add     = "Subject: [$local_part] ${sg {this is a [test] for \
           not having done so}{\N\[\w*\]\s\N}{}}"

 > headers_add     = "Subject: [$local_part] ${sg {this is a [test] for \

                    not having done so}{\N\[\w*\]\s\N}{}}"
headers_add     = "Subject: [] this is a for not having done so"

###### the Auth section #######
begin authenticators
# annika als server
# fixed_cram:
# driver     = cram_md5
#  public_name   = CRAM-MD5
#  server_secret = ${if eq{$1}{bambole}{oRn2hoLb}fail}

# annika als client gegenueber calisto als smarthost
fixed_login :
   driver     = plaintext
   public_name    = LOGIN
   client_send   = : smtp : hepwsm

   ##### Character Test #####
   # denies bad characters in the local part for local domains
#  deny    domains       = +local_domains
#      log_message   = $sender_host_address has bad characters
#          local_parts   = ^[.] : ^.*[@%!/|]

   # and be less restrict with all other (routed) domains
#  deny    domains       = !+local_domains
#      log_message   = $sender_host_address has bad characters
#          local_parts   = ^[./|] : ^.*[@%!] : ^.*/\\.\\./

   ##### accepts the postmaster@ for all domains listed in local_domains 
but only sent from worf or localhost #####
   accept  hosts        = worf : 127.0.0.1
      local_parts   = postmaster : root
           domains       = +local_domains

   ##### check of the sender could be reached (basic verification checks 
only the domain) #####
   #  require verify       = sender

   ##### Accept without auth only, if from worf or localhost #####
   # accepts the incoming recipient address if its domain is one of the 
local domains
   accept  hosts        = worf : 127.0.0.1
      domains       = +local_domains
           endpass
           message       = unknown user
           # verify        = recipient

   ##### the end #####
   # if a msg reaches this, it will be denied (cause its the end, baby)
   deny    message       = relay not permitted

# checks if the msg is spam-tagged and user want's to keep it. else delete
   delete_spam:
    driver         = accept
    local_parts    = ! /etc/exim4/spam.lovers
    condition    = "${if and {\
                {def:h_X-Spam-Status:} \
                {match {$h_X-Spam-Status:}{Yes}} \
               } {1}{0}}"
    transport    = sent_to_bin

# checks, if the user is in /etc/aliases and replaces them accordingly
   system_aliases:
       driver         = redirect
      allow_fail
       allow_defer
       data         = ${lookup{$local_part}lsearch{/etc/aliases}}
    # user         = exim
       file_transport     = address_file
       pipe_transport     = address_pipe

# checks, if the mail is sent to a mailinglist
   lists:
    driver        = redirect
    file        = /etc/exim4/lists/$local_part
    headers_remove    = Subject : Reply-to
    headers_add    = "Subject: [$local_part] ${sg {this is a \
               [test] for not having done so\     
               }{\N\[\w*\]\s\N}{}}"
#    headers_add    = "Subject: [$local_part] ${sg {$h_subject: \
               }{\N\[\w*\]\s\N}{}}"
    forbid_pipe
    forbid_file
    skip_syntax_errors

#handles all connections except @bambole.ch & @annika.labex.ch
   dnslookup:
    driver         = dnslookup
       domains     = ! +local_domains
       transport     = smarthost
       ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
       no_more

# after all, only valid localusers stay (otherwise it get's bounced)
#  localuser:
#      driver         = accept
#      check_local_user
#      transport     = local_delivery

# after all, only valid localusers stay (otherwise it get's bounced)
   procmail:
       driver         = accept
       check_local_user
       transport     = procmail_pipe

# deletes the message without further notice
   sent_to_bin:
    driver        = appendfile
    file        = /dev/null

# schickt alles an calisto
smarthost:
    driver         = smtp
         hosts        = calisto.umlaufbahn.ch
    hosts_require_auth = calisto.umlaufbahn.ch
    hosts_override    

# deliver over SMTP, all options are default
   remote_smtp:
       driver         = smtp

# deliver local
   local_delivery:
       driver         = appendfile
       file         = /var/mail/$local_part
      delivery_date_add
       envelope_to_add
       return_path_add
       group         = mail
       mode         = 0660

# deliver through procmail
procmail_pipe:
    driver         = pipe
    command     = /usr/bin/procmail -d $local_part
    group        = mail
    check_string    = "From "
    escape_string    = ">From "
      delivery_date_add
       envelope_to_add
       return_path_add

# handles connection over pipes (used by /etc/alias)
   address_pipe:
       driver         = pipe
       return_output

# handling delivers to files caused from redirection (etc/alias)
   address_file:
       driver         = appendfile
       delivery_date_add
       envelope_to_add
       return_path_add