showing project reference details in OTBI

Content

We are trying to union both
Project Costing - Actual Costs Real Time and Payables Invoices - Transactions Real Time
or Project Costing - Actual Costs Real Time and Costing - Receipt Accounting Real Time

so we can show a report with actual project cost and reference details like invoice number , invoice line description , receipt number , PO number and PO line desc.

the problem we are facing that Project Costing - Actual Costs Real Time subject area has reference IDs not actual numbers however the payables and receipt subject areas do not have IDs so we can not link both subject areas using set operation UNION available in oracle transnational business intelligence.