Legacy Data creation in BCS
Please guide me on how at the time of going live in BCS FS items are created. For e.g in our ECC / R/3 we have defined FS Items, now the same would be used in BCS. Do we create all our ECC FS Items manually in BCS or is there any method through which we upload FS Items from ECC to BCS. Like when we go live in R/3 or ECC system from Legacy system, there we make upload programs (BDC) to load all Master Data of Legacy system to SAP. In BCS how is Maters copied from R/3 or ECC.
Many thanks to all,