[Dovecot] FTS autoindex problem

[lee_yiu_chung@yahoo.com]

I tried to implement a solr search server, but I found some unexpected behaviour when I turn on 
autoindex according to http://wiki2.dovecot.org/Plugins/FTS.

I found that all autoindexed email are using "user1 at example.com" as username, as shown in maillog:

indexer-worker(user1 at example.com): Indexed 1 messages in INBOX

However, all manually indexed email (triggered by IMAP server search) are using "user1" as username, 
as shown in maillog:

indexer-worker(user1): Indexed 2927 messages in INBOX.

I am using "user1" as login name, so all autoindexed mails don't appear in search result. How can I 
use "user" as the username in autoindex?

BTW, I do have a few mailboxes in the format user2 at virtualmail.example.com, which requires full 
email address as the login name. How can I autoindex emails that automatically distinguishes 
user1 at example.com (using "user1" as username) and user2 at virtualmail.example.com (using 
"user2 at virtualmail.example.com" as username) given that the previous question is solved?