[exim] fakereject usage and redirecting SPAM mail to a local…

Hi fellow Exim users

I have setup a route as follows to locally deliver a copy of ALL mails to a
local user as follows:
--- snip ---
  corpus:
    debug_print = "R: corpus redirect"
    driver = redirect
    domains = xxxxxx.xxx.xx
    data = mailspool@$primary_hostname
    unseen
--- snip ---

I am hoping to do the same for my SPAM checks

In my DATA acl I have the following:
--- snip ---
  deny    message    = SPAM detected ($spam_score)
          condition  = ${if <{$message_size}{1536k}{1}{0}}
          hosts      = !+spam_exclusions:!+relay_from_hosts:*
          senders    = !@@partial0-lsearch;CONFDIR/lists/white.list
          spam       = nobody
          condition  = ${if >{$spam_score_int}{60}{1}{0}}
--- snip ---

I was thinking of changing this to:
--- snip ---
  warn    control = fakereject|SPAM detected ($spam_score)
          condition  = ${if <{$message_size}{1536k}{1}{0}}
          hosts      = !+spam_exclusions:!+relay_from_hosts:*
          senders    = !@@partial0-lsearch;CONFDIR/lists/white.list
          spam       = nobody
          condition  = ${if >{$spam_score_int}{60}{1}{0}}
--- snip ---

I DON'T want this to be delivered to the users at this point but rather
just locally spooled to mailspool@$primary_hostname.

The idea is to build a SPAM/HAM training mechanism which can then also
allow a quick delivery of False positive SPAM Mails.

I was thinking of doing this via Header Rewrites. Can someone suggest a
**clean** way of doing this.

Or even other alternative ways entirely. Am still very much an exim newbie.

--
Regards

Andrew Gargan