[PERDITION-USERS] Thunderbird IMAP interaction and capabilities

Hi, I've found a small problem in the way perdition interacts with thunderbird to do with capabilities. We look up our users in ldap to get their mail server, some of which have different capabilities. When Thunderbird connects to the perdition proxy, it sends a capability command after connecting and again after a starttls command but it doesn't send it after a login command. The RFC says it is possible for a server to send CAPABILITY results in the tagged OK response to a successful LOGIN command. Is it possible to have perdition either proxy the OK response of the server instead of sending it's own as the server is sending the capabilities in the OK response, or have perdition send a CAPABILITY command to the server and create an OK header from the result? Thanks, Duncan