Events can be triggered on many different conditions, also on custom properties values.
Notice the first condition. It contains the value: data~machine~properties~SopraInternal.UseCommonEB2
This can be set either in the Custom Attribute attribute in the IaaS blueprint:
Or you can set it directly in the JSON data if you call the IaaS bluerprint from vRO (EG: using XaaS as a blueprint to call IaaS blueprint)
json.vSphere_Machine_1.data["SopraInternal.UseEB2"] = true;