Using Requestor level data page to map Operator attributes in the Mapping tab works.
The source activity of the Data Page loads data from D_SAMLAssertionDataPage.
But the challenge now is - based on the assertion attributes, we need to load some other data from internal tables on to the Operator Page and this is list data which has to be stored in embedded Pagelists on the Operator Page.
Data page is properly loaded with all this data but how do load this list data on the OperatorID Page? Mapping tab is only for scalar property mapping. Providing an option for Data transform in the Mapping tab should have helped.