Hi Akshay,
BPC 10.1 unified means that you can directly use input-ready BEx queries in EPM Add-In, you don't have to enable this for 'external access'. Just as a simple test create a connection of type 'SAP BW (INA Provider), logon to the back-end system, choose your BPC environment and model and then you get the search dialog for BEx queries.
Regards,
Gregor