Spam Default Folder

Hello.

I need to change the default SPAM folder, which is being created in a subfolder of INBOX.

I want:

Inbox
Trash
Spam
Sent

Currently my Plesk creates:

Inbox
--Spam
Trash
Sent

I can customize the folder by Dovecot but that messages are no longer sent to the spam folder automatically.

Where can I change this setting?

Tanks!