We here at Utah State University Cooperative Extension have been using
W4Wg for a while now.  We wanted to talk to the internet with the mail
package so we got the smtp gateway.  You also need a tcp/ip transport
package on top of that which is utterly stupid but that's what they
require to get the smtp gateway to work.  You need a dedicated pc
for the gateway and if you are looking at remote access you need another
dedicated pc for the remote mail stuff.  We do not have the remote mail
going but you indicate that that is what you want to do.  

There is a glitch somewhere in the system though.  I don't know if it
is MS mail, the gateway or the VAX here on campus that is choking in the
mail that is sent.  The scenario is this.  The outgoing mail goes to a
Unix system which then routes the mail where it needs to go.  If that mail
is routed to the VAX, the VAX has problems some times receiving the mail.
Most messages do get through this way except if someone has there mail
on the VAX forwarded to some other location.  That is the main gotcha.
Where ever the mail is forwarded to that person gets a message header
then a message saying "Boudary:= (error garbage code stuff)".  If you
can stay away from sending to a VAX you are ok.  The system people
of course say that the VAX is not the problem, the gateway is probably
the problem.  If anyone wants to get help it is only $175.00 for one
support call. (until problem is worked out)  Phooey to that I say.  I
am looking vigorously for a better Idea.  

If you go forward on any of this and find out anything knew,  please
drop me a note - anyone.  The next itteration is supposed to have tcp/ip
built in THEY say........  The netxt itteration of w4wg

Good Luck!!!!!