[Exim] Maillist problem

Hi,

I'm trying to setup a mailing list that will remove the read receipts from
message but my configuration seems to be ignoring the headers_remove option
(and headers_add if I put it in).

Any suggestions ?

Thanks,
Jeff.

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Config on Exim 3.16. (I've changed the domain in the example)

lists:
driver = forwardfile
domains = fred.org
local_parts = testlist:admin
require_files = /home/fred/lists/$local_part
senders = /home/fred/lists/$local_part
file = /home/fred/lists/$local_part
headers_remove =
"return-receipt-to:acknowledge-to:disposition-notification-to:x-priority"
no_check_local_user
forbid_pipe
forbid_file
forbid_include
forbid_filter_logwrite
forbid_filter_reply
one_time
skip_syntax_errors
syntax_errors_to = postmaster@???
errors_to = postmaster@???