SQL Server Reporting Service - Refresh Problem

Hi .
I am using SQL Reporting services for my Report.

I am using rs:clearsession=true for refreshing of report data from my page.i had passed
rs:clearsession parameter from aspx page to report URL, but when i am navigating from parent
report to child report then rs:clearsession is not appended.

so is there any way by which we can set some property in reporting service and we can get
the result of "rs:clearsession" variable in itself report.

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rs:clearsession=true  // I am using it for fetching the updated data from DB

Thanks in advance,