dovecot - Aug 2007 - How do I use sieve to move bounces?

How can I use sieve to move bounces and non delivery reports (i.e. 
anything with an empty envelope from) to a special mailbox? I placed 
this snippet at the start of my sieve script

require ["envelope", "fileinto"];
if envelope :is "from" "" {
     fileinto "INBOX.Reports";
     stop;
}

But mails are not moved to the reports mailbox, and they are still 
processed by the rest of the script.

Jef Driesen wrote:
> How can I use sieve to move bounces and non delivery reports (i.e. 
> anything with an empty envelope from) to a special mailbox? I placed 
> this snippet at the start of my sieve script
> 
> require ["envelope", "fileinto"];
> if envelope :is "from" "" {
>      fileinto "INBOX.Reports";
>      stop;
> }
> 
> But mails are not moved to the reports mailbox, and they are still 
> processed by the rest of the script.
To answer my own question, this script seems to work for me:

if header :is "Return-Path" "<>" {
    fileinto "INBOX.Reports";
    stop;
}