I am running a Zimbra OSE 8.0.4 on Ubuntu 12.04

When i mark mails as spam in the webmail then they are moved to spam folder.
In thunderbird that is connectet via IMAP they are still in inbox.

I have sent 50 mails with same text from same sender to the Zimbra mailbox and have all marked as spam.

When i send the same mail then thay are not marked as spam or moved to spam folder.
How can i mark spams that the are auto moved to spam folder ?