[otrs] Insert "Sender: <agent_mailadress>" Mailheader in outgoing mails?

Where can I configure in OTRS to insert a "Sender: " so the Mailheader would like this: ... From: support@example.com Sender: agent_mailadress@example.com .... We want that our customers can see which Agent (=mailadress) sent the mail response. e.g. Lotus Notes client can display it as "Sent by cervicek@example.com". We use OTRS 2.4.7