gmail config on web.config

Hi,

I'm using the default security login control (login, forgot password...)
I've trouble as gmail.com user to send e-mail for new password, regarding the STARTTLS command.
I already wrote this in my web.config :

 <system.net>
  <mailSettings>
      <!--
   <smtp from="yahooname@yahoo.com.sg">
    <network host="smtp.mail.yahoo.com.sg" password="xxxxxxxxxx" userName="yahooname"/>
      </smtp>
      -->
      <smtp from="gmailname@gmail.com">
        <network host="smtp.gmail.com"  password="xxx ...