pop3 password

Hail list! I have a small pop3 server! Somehow i've lost /etc/shadow and since then my user can't log in! The authentification is plain text! So... what i want is to capture the password the user sends to me with his pop3 client on pass negociation so i can change the password wright for my new /etc/shadow! i've tried some pop3 servers (qpopper, solid-pop3d, courier) but none of them let me see the password (e.g. like "show-password" for ppp)! so... how to sniff the pasword? Danke!!!!