[exim] How to use fake reject?

Dear list,

after searching the archives and faqs, my question keeps unanswered:

What is the (best) way, to use the fake reject control?

As my rcpt_acl starts with a lot of drops/denies (not without a reason),
where should I implement the 'control=fakereject' to get all the unknown
recipient's mail delivered for further inspection to the postmaster AND
bounced back to the sender (because the postmaster doesn't work 7/24)?

Most messages stop here:

drop message   = Recipient unknown
!verify        = recipient
delay          = ${eval: ($rcpt_fail_count + 1) * 1}m

So, what kind of accept should I add before, to get all unknown recipients
fake rejected and in copy delivered to the postmaster?

I think, simply adding it before, there will be two bounces to the sender?

Thanks,
Sebastian