[otrs] Customer notification of added note

Hi Everyone, If my interpretation is right, when I add a note to a ticket I get two options, Note-Internal and Note-External, I assume that Note-Internal is used for agents only, and Note-External is used for customers and is therefore visible via the customer logon. What I would like to do is when I add a note to a ticket, the contents are sent to the customer of that ticket via e-mail. Does anyone know how I should go about this? Thanks, David