Dim oMsg As new System.Web.Mail.MailMessage()
oMsg.Fields.Add( _
  "http://schemas.microsoft.com/cdo/configuration/smtpauthenticate", "1")
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", _
UserName)
oMsg.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", _
Password)