SRM 3.0 - Sourcing cockpit from BBP_PD - header and items links tables

Hi all,

We're on a SAP SRM 3.0 configured for an extended classic scenario. Looking at the transaction BBP_PD for a Shopping Cart created with ref. to a Purchase Requisition (from an R/3 system), we can see that there are two sections, called respectively "Header links" and "Item links". This is an example for a SC created from the PR 1000004268:

Obj_Key: HEADER

Obj_Type: BUS 2121

LogSys: RCDCLNT100 (our srm system)

RoleType: BBP_TARGET

<<<<

Obj_Key: 1000004268 0000000000

Obj_Type: EXTREQ

Logsys: our_R/3_backend_system

RoleType: BBP_SOURCE

A similar entry is available for each item of the shopping cart.

Question: where are these data stored? Which tables are involved in this relationship determination?

The question arises since we're currently trying to migrate some documents from a certain logical system to another; this task implies also a conversion of data for some documents in SRM which must be modified in order to make them refer to the newer logical system (say, B) by changing every field value which refers to the older logical system (say, A). Obviously, for what that concerns these documents, B is exactly identical to A.

Thanks in advance 😉