How do I get the added domain footer so it also appears in the senders copy of that mail in "Sent Items"? I'm asking for a law firm who needs to prove that the receiver indeed got the footers "legal text". It's works, but the sender never sees it and therefore cannot prove the receiver actually got to read the legal (i.e. read the mail in his/hers mail client).

We now use client-based HTML signatures that works fine, but the servers ability to add a dynamic footer would be awesome to use instead of this.