### Sender options
# Set up sender 
set envelope_from
set realname = "Tim Lupfer"  
set from = "tl at assimilated.org"
set hidden_host = yes
set hostname = "assimilated.org"

That seems to do the trick for me, I believe 'set envelope_from' is
the important part.

-Tim
-- 
==============================================
timothy lupfer      http://www.assimilated.org
tl at assimilated.org tlupfe01 at euclid.hamline.edu
==============================================

Don't go around saying the world owes you a living.  The world owes you
nothing.  It was here first.
		-- Mark Twain