We've just made changes to the rules for 1.17 that allows you to create a forwarder overtop of an existing pop account. I believe that it will still not allow you to add a forwarder for the system account ... I'll make the change for the next release. This change will also allow you to set any forwarder straight to the system account "username" instead of "[email protected]"... if you ever want to get email to you system pop account ever again, you'll have to set the forwarder to forward to just "username" (not [email protected]), to prevent an infinite loop.