Hi Jerry,
In the Web Client UI, I think the data that you are talking about is being fetched by the relationship -
BuilOpportunityRel which you can find in the Genil Model BP(Business Partner) - Root Object BuilHeader. This will in turn call the GENIL API's which will execute the application logic or will trigger the CRM Business Engine.
You can put a break point in the Class : CL_CRM_BUIL Method - GET_OBJECTS. This will provide you with the entry point from where you can get the road to access the API for Search.
I will try to figure out the code or logic along with the core API if there are some data in the system.
Hope this helps.
Thanks,
Samantak.