Dovecot: doveadm sync namespace | single folder

I am trying to make sync (or sync -1) for single folder. Forwarding the manuals, we can use -x flag to exclude folders - it works fine. Also, there is -n flag to sync namespaces. As i see, there is no way to sync folders like with -x flag, but i guess that i can preset some namespace (for example: namespace myns{...}), and then use something like: dsync -1 -n 'myns' to include only folders that i have specified in that namespace. But it does not work, or i configure it wrong.

So, please, help me to write the right config or just clarify that it does not work or that I misunderstood the manuals.

Currently using simple INBOX namespace like:

namespace inbox {
    type = private
    separator = /
    prefix =
    inbox = yes

    # Sent
    mailbox Sent {
        auto = subscribe
        special_use = \Sent
    }
    mailbox "Sent Messages" {
        auto = no
        special_use = \Sent
    }
    mailbox "Sent Items" {
        auto = no
        special_use = \Sent
    }

    mailbox Drafts {
        auto = subscribe
        special_use = \Drafts
    }

    # Trash
    mailbox Trash {
        auto = subscribe
        special_use = \Trash
        autoexpunge = 30d
    }

    mailbox "Deleted Messages" {
        auto = no
        special_use = \Trash
        autoexpunge = 30d
    }

    # Junk
    mailbox Junk {
        auto = no
        special_use = \Junk
        autoexpunge = 30d
    }
    mailbox Spam {
        auto = subscribe
        special_use = \Junk
        autoexpunge = 30d
    }
    mailbox "Junk E-mail" {
        auto = no
        special_use = \Junk
        autoexpunge = 30d
    }

    # Archive
    mailbox Archive {
        auto = no
        special_use = \Archive
    }
    mailbox Archives {
        auto = no
        special_use = \Archive
    }

    # Virtual box All Mails
    mailbox virtual/All {
        auto = no
        special_use = \All
    }
}