Trucos de ASP.NET Enviar email con servidor SMTP que requiere autentificación

Para poder enviar un email a un servidor SMTP con autentificación es necesario enviarlo así:

Dim email As New System.Web.Mail.MailMessage
email.From = "mail@from.com"
email.Fields ("http://schemas.microsoft.com/cdo/configuration/smtsperver") = "SMTPServerName "
email.Fields("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25
email.Fields("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2

email.Fields("http://schemas.microsoft.com/cdo/configuration/smtpauthenticate") = 1
email.Fields("http://schemas.microsoft.com/cdo/configuration/sendusername") = "SMTPAUTHUser "
email.Fields("http://schemas.microsoft.com/cdo/configuration/sendpassword") = "SMTPAUTHPassword"
email.To = "destinoi@mail.com"
SmtpMail.SmtpServer = "tu_server_smtp"
SmtpMail.Send(email)