You should create a file called dboptions in your ISL Conference Proxy installation directory with the following content:
light_external_id=1 islpronto_external_id=1
Once you save this file you need to restart ISL Conference Proxy to apply it.
When the server comes back up you will see an additional column called "External ID" in the ISL Light and ISL Pronto session history. This column is indexed so it is possible to perform webapi2 queries on it. Our ISL Light integration example will use this field to store the appropriate BMC ticket id.
You are now ready to proceed to the next step of integration.