[Exim] condition and exists{}

hi!

i have the following problem with simple list handling with v4.10:

lists:
driver = redirect
condition = ${if exists{/etc/exim/lists/$domain/$local_part.acl} {yes} {no}}
require_files = /etc/exim/lists/$domain/$local_part
senders = lsearch;/etc/exim/lists/$domain/$local_part.acl
file = /etc/exim/lists/$domain/$local_part
headers_remove = "Sender:From:Envelope-to:Organization:Return-path"
headers_add = "From: $local_part@$domain\nEnvelope-to: $local_part@$domain"
no_check_local_user
forbid_pipe
forbid_file
skip_syntax_errors
errors_to = $local_part@$domain

this should be evaluated only if the condition is true, but exim always
stumbles into the senders-file and reports an errer, the file doesn't exist!

any hints on this?

regards, --- jan.