[Dovecot] Quota plugin and SQL

I have read through http://wiki.dovecot.org/Quota/Dict, which suggests a database schema for using quota. For 1.2, this includes a username, bytes and messages.

Is there any way to modify the queries used to split out username into localpart and domain? This would enable me to put the current quota information in my main mailbox table and display it to users in my admin interface.

Or possibly it should be in a separate table for a reason, and I should be look there for the values?

Thanks,

David