Is there a way to request special attributes from LDAP?

[offby0point5]

The organization I'm building a mail setup for has a generated username for everyone to use as login. Additionally, everyone is allowed to have aliases like their nicknames. These accounts are stored in a backend that is reachable over LDAP.

I've got the IMAP login over LDAP working using the dn_template option.
Binding to search for a user fails, as Maddy seems to hard-codedly filter for the dn attribute, that the backend does not specify (at least when asking for it directly). This is not a fault of Maddy, so I wouldn't ask to change this behavior based on this problem.

But now that users can authenticate I want to read their allowed mail addresses from LDAP in the submission > check >authorize_sender block so using auth.ldap as table is only supported with search bind. But neither can Maddy search for users due to the hard-coded dn attribute filter nor could I list all mail attributes as allowed sender addresses for a user.

Am I missing something or is this not yet implemented?