how perfrom data quality check for SAP BW with BC data source by data service

Hi expert,

          I know how to integrate data quality check with sap bw if external data source is going to be brought into sap bw. but how to do data quality check whenever SAP bw extract data from SAP application system directly using business content?  in the case, I know we can do data quality check by ABAP programming, but if I want to use data service to do data quality check, where to put in data service ? and how to make data service interface with SAP BW?

Many Thanks,

Andy