[exim] Submission mode: change return path without adding Sender: header?

Is it possible to configure submission mode so that the return path of a message is set to the $authenticated_id, but there is no Sender: header created? I'd like to trust my users to set whatever From: address they like, but still ensure that bounces go to the authenticated sender address. But

Re: [exim] Submission mode: change return path without adding Sender: header?

On 2008-02-12 at 15:00 -0500, Marc Sherman wrote: Is it possible to configure submission mode so that the return path of a message is set to the $authenticated_id, but there is no Sender: header created? How about using control = submission/sender_retain and a rewrite in ye olde rewrite