I mostly wish to redirect (bounce) an email to the sender, but the senders email address does not appear in the box, I have to insert it myself, a message that the mail was not required could also be added.
This review is for a previous version of the add-on (0.8.5).
Sorry, but this extension is not for this purpose. To bounce back letting the sender think the address is unknown, would require complete other logic (and doesn't have much use for spammers anyway) and changing the message by saying the mail was not required is also not according to the specs of redirecting. You should use a normal reply message for that.