At home, I read and compose my email with VM in Xemacs.  The only
problem wiht this from my standpoint is that sometimes it takes a long
time to send a message and the emacs will block while the SMTP
transaction goes on.

So I had the idea of installing sendmail and using envelope
masquerading and a smart host (there's a sendmail-address-rewriting
HOWTO about how to do this).  Then my email would just leave emacs and
be slurped up by sendmail, effectively instantaneously, allowing me to
progress.

Well, the smart-host configuration is working like a champ, but the
envelope masquerading isn't.  Just doesn't seem to do anything.  When
I look at mail I send out through sendmail, I just see

<my-user-id>@localhost.localdomain

I can't find anything in the sendmail doc to explain how to
troubleshoot this kind of problem.  No options that suggest how to
watch a piece of mail enter sendmail and walk through all those rules
(and rules and rules and rules....).  Anyone have any suggestions?

I suppose another alternative would just be to make myself a
trusted_user and then have emacs do the envelope masquerading....

Thanks,
R