I think I've got it working.
How did you get it working? Why was it not working?
Well I think partly it was down to my mail provider.
I did originally do what you mentioned, the
config set SMTPSmartHost "smtp.myisp.com:587" and 
signal-event email-update.  Unfortanately I couldn't get it working.  I think it might have been my mail provider still blocking something.
After messing around with Thunderbird, I determined that my ISP doesn't allow e-mails using SSMTP, but they do require authentication.
I altered the outgoing SMTP server using the server manager which I'm guessing broke things.
Anyway, after doing the config set command again, and changing the e-mail providers SMTP server to yet another SMTP server which was given by my provider, it seems to be going through.
I did notice there is a few seconds delay between the SME server receving the mail and sending it on, but thats no major problem.  It works and thats the main thing.
Now all I have to do is get my router to allow through SHTTP which I seem to have configured incorrectly. 

Rob