Drill down customized reports.

Dear Friends,

I have already reports (all in PDF format) for tracking for Procure to Pay Cycle, my requirement is to create a drill down link to other report in existing reports for example in Payment Invoice report Purchase Order Number or PO Receipt column dynamically linked with Purchase Order Report or PO Receipt report and so on.

to achieve this a format trigger is created as per below code

but drill down report is not found, as above snap. by default concurrent request is called as below url , the reason behind not opening the linked output is difference methods of calling report, is there any fix or clue anyone have regarding this issue, please help to fix.