[Dovecot] Automatically subscribe to folder?

[Christian Flothmann]

Hello everybody,

i am filtering e-mails using the cmusieve-plugin. A global script filters
all mails tagged by SpamAssasin and moves them into the folder Spam:

if header :is "X-Spam-Flag" "YES" {
    fileinto "Spam";
}

My problem is that users who did not had a folder Spam until the first
time of filtering a spam mail are not automatically subscribed to this new
created folder. They have to do this step manually in their mail client.

Is it possible to automate this script and subscribe the account to this
folder when it is created by the sieve script?

Regards,
Christian