Hi Isabelle,
My name is Hank Schrandt and I am the SAP Product Owner for the Aerospace & Defense software. When I was a consultant not too long ago, I recognized the need to have "Item" level data at the Project Level that are on the original cost postings to the PO Items and Production Orders stored on the COEP cost table.
The problem as Thomas Pohl mentioned is that GPD Distributes costs using the PEG_TASS table data to map to which projects the costs belongs to at a summary level.
SAP is developing a supplementary report to provide this data (Vendor number, Material Number, Original CO Document Number and posting row, Original posting date & original doc date, created by ID#, personnel number, operation number on production order, the entire pegging record related to the costs, etc...) CJI3 will not show this info. This requires capturing a copy of the GPD pegging data (PEG_TASS table) after each "Full" GPD Distribution run. or for the last GPD Distribution Run prior to Billing where it makes sense for your business process.
This design is intended for ECC SoH platforms because of the large amount of data. This could [possible be done in "ECC not on SoH" if the copies of GPD Pegging has an archiving strategy to keep this new table to a manageable size.
This solution should be available sometime around the end of 2014.