Open up Code Setup and go to messaging. Open message definitions, and click on the insert button. Fill in the sections as follows:
Code: Create a Wetu code - example - WETU\
Description: Describe what message code this is - example - Wetu Messaging Template\
Type: Set this to - Booking XML message\
Editing Destination: None
Please make sure you set up the template as **Type - Booking XML** as per the screenshot (Your code and description can be as you wish).