I have the same issue and i cant seem to be able to convert my url for a drill through report to the required format

This is my report url

http://ReportServer/SQLREPORTs/report/Accounts/Management%20Information/Lost%20Clients/PBS%20UKI%20Lost%20Clients%20Reports/Client%20-%20Monthly%20Client%20Summary%20Detail%20by%20Signed%20On

the parameter i would like to pass is Ledger=ldg

Can anyone help with the code to open it in a new window please.

Thanks in advance