Secure SMTP send setting?

[Nigel L]

Following relates to latest MozMail:
I just signed on with a free UK-based web\POP\IMAP e-mail service.  I 
have added it as a second IMAP service.  It works just fine, even though 
mail client instructions for Netscape 4.08+ only mention POP.  However, 
the web site cautions that in March they will switch to "Secure SMTP" 
for sending.  They offer screenshot instructions for Outlook Express 5+, 
 but not NS or Moz.  Where is the setting for this in Mozilla?
                                                                        
                                                  Rgds,
                                                                        
                                                           Nigel L