You can add a forwarding email account to the .forward like this:
\username, firstname.lastname@example.org, "|/usr/bin/vacation username"
This will send a copy of the message to username@localhost _and_ email@example.com, plus reply to the sender with the auto-response that you set up in the .vacation.msg
With a little side of applesauce...
©2006 Shannon Eric Peevey