[otrs] Customize customer notification

Hi list, I am trying to customize the customer notification for state change so that it shows the closing note written by the operator (the text written in the the text area when closing the ticket). So far I have tried: OTRS_BODY, OTRS_COMMENT, OTRS_CUSTOMER_DATA_BODY but without success. I have looked at the code and I'm ready to hack it, but before I do I wanted to ask on the list. I am running otrs 2.0.4. Any help will be very much appreciated, Umberto