Dear Taniya,
1) First get a project definition in ecc which carries all relevant data in dev system.
2) Run RSA3 for the relevant data source and check whether the datasource is brining in the correct data for eg 0co_om_wbs 1,3,6 & other datasources,
3) Functionaly it will depend on how planning is done for cost and revenue (CJ40/cj42) in ECC. so check whether they are doing at the cost element or at a particular wbs level.
4) The 0CO_OM* data source can be categorized into two, one brings the planned value and other actuals. For eg 0_CO_OM_WBS_6 brings actuals for wbs related actuals
There are no other specific change to be done in ECC to populate data for this.
Regards
Gajesh