While you may not want to use CDO, this is what I use and I find it pretty easy-to-use and it works well.
So... that doesn't answer your question, but I'm hoping it might make your life easier using CDO. My other suggestion would be along the lines of what Spudhead says - find some 3rd party software API you can plug into.
' email address passed in from form
Dim email = request.form("email")
' send message to person who filled out the form
confirmMessage.Subject = "Contact Us"
confirmMessage.To = email
confirmMessage.HTMLBody = "<p align=left><font face=arial size=2>"
confirmMessage.HTMLBody = confirmMessage.HTMLBody & "Thank you for contacting us!<br><br></font></p>"
set confirmMessage = Nothing