CRM Cloud for Customer Activity (Appointment Task) External ID Table

Hello,

I'm trying to compare the activities in Cloud for Customer (Appointments, Tasks) with CRM (we replicate from C4C to CRM).

I can get a list of Tasks and Appointments in Cloud for Customer easily, and can Personalise the search results screens to have the "External ID" field. This tells me the OBJECT_ID for table CRMD_ORDERADM_H in CRM. So I can see a relationship between C4C ID and CRM ID for a task / appointment in C4C.

But I would like to know where CRM stores the CRM ID - I assume there must be an entry in a table which maps the CRM OBJECT_ID (or GUID) from CRMD_ORDERADM_H.

Does anyone know which table this is? I've tried the ..ORDER_INDEX table and was thinking about a document flow table - but I'm not sure.

Thanks, Chris