I can (unofficialy

) say that the "multiple SMTP servers" feature is actually present even in version 4.0.235. It's there, but it's just hidden.
To use it, use the following method:
Insert this line
UseDefaultSmtp=0
to file C:\Program Files\ALWIL Software\Avast4\Data\Avast4.ini into section [MailScanner]. Terminate process ashMaiSv.exe and restart it.
Change account settings of your mail program this way:
SMTP server: 127.0.0.1 (it is already set by avast)
Turn on authentication for SMTP.
Login name for SMTP:
#SMTPSERVER
(obviously replacing SMTPSERVER with your SMTP server address) (If you already use SMTP authentication, append #SMTPSERVER to your name.)Don't turn on secure authentication.
Hope this helps,
Vlk