[exim] reject mails via .forward not bounce

Hi list,

I tried to reject files via .forward which looks something like this:

| if bla ....
| elif ..
| ...
| else
| fail
| finish
| endif
| ...

The problem is that all those mails which come into the "else fail
finish" part are bounced back instead of rejected (smtp code 5XX is what
I am looking for).
I tried "hide_child_in_errmsg = true" in the router's section but whith
no luck. Is there an option in the router | transports section which I
forgot?
Another way (not to accept message and not to bounce back) is to use
"seen finish" statemant but in this case the sender does not know that
the message sank in black hole and I don't want this.

The userforward part of the config:
| userforward:
| driver = redirect
| file_transport = address_file
| pipe_transport = address_pipe
| reply_transport = address_reply
| check_local_user
| directory_transport = address_directory
| local_part_suffix = +* : -*
| local_part_suffix_optional
| file = $home/.forward
| allow_filter = true
| allow_fail = true
| no_verify
| no_expn
| check_ancestor = true
| hide_child_in_errmsg = true

Other section are the same as in exim.conf.dist

--
Regards
Sebastian Siewior