Migration of portal reports

Hi,

I am about to embark on report migration project in EP and I have not much portal experience.

Customer requirements is that they login to the old Portal (Abap web) and when they view report they should get the the reports from the new Java web ( server)

current the system landscape is that they view reports from BI via old java web.

ABAP web -> BI

and now they want to view report from like this

ABAP web -> Java web -> BI

any imput will be welcome.

thanks