email customer a copy of external note

[holmesmail]

Is there a configuration parameter that allows the automatic emailing of an external note added to a ticket?

[jojo]

no, if you wan't to mail the customer use the Compose Answer functionality

[crythias]

I think a notification (event) can be used?

Edit: While true, JoJo's answer is preferred. If you're going to take the trouble to create the note external to email it, you might as well use a Response.