Yes, with server-side enabled, you add the 'marker', and the recipients will see the email signature assigned for NEW emails:
Copy the 'marker' and try it now:
{EMAILSIGNATURE}
Note: This feature will not work for emails coming from free mail providers or personal mailboxes. Messages coming from Gmail, Hotmail, or Yahoo will fail to receive the Autoreply messages unless you exclude them from the rerouting. Please refer to THIS KB for more details.