open table RSOSFIELDMAP,
Try to see the display data.
in field name - enter ANLN1 and hit display .
it will shows bw objects in info objects column.
Even you can enter OLTP source as data source name and see ecc fields and bw objects in different columns.
if you see table you will find what you need. later you can install them from bi content.
Field bw info obejcts
ANLN1 - 0ASSET_MAIN
AUFNR - 0CCORDER