[Exim] ACL help?

I have been scratching my head over this one over the weekend now.

I have the standard(?) ACLs listed below, and I want to add a blacklist
for a few troublesome mail domains. But regardless of how I try to
modify the ACL, I can not get this working. I have seen tons of error
messages, and weird behaviour, so please oh ye exim-4.12-gurus, how do I
add a blacklist-on-domain-name that uses lsearch in a file for the
domain names?

acl_smtp_rcpt = check_recipient
acl_smtp_data = check_message

egin acl

#!!# ACL that is used after the RCPT command
check_recipient:
  # Exim 3 had no checking on -bs messages, so for compatibility
  # we accept if the source is local SMTP (i.e. not over TCP/IP).
  # We do this by testing for an empty sending host field.
  accept  hosts = :
  accept  domains = +local_domains
  accept  domains = +relay_domains
  accept  hosts = +relay_hosts
  accept  hosts = +auth_relay_hosts
          endpass
          message = authentication required
          authenticated = *
  deny    message = relay not permitted

#!!# ACL that is used after the DATA command
check_message:
accept