[Dovecot] How can I see the last login time vuserinfo when I login to imap server ?

Hello

I use dovecot-1.0.7 for imap. I also use vpopmail5.4.x. on qmail.

It works well so far. But when I log in to imap server, I could not see the last login time vuserinfo command in vpopmail.

How can I correct that ?

Thanks.