How to filter form datasource when called from SSRS drillthrough URL action

Hi,

I am able to open vendInvoicejour from SSRS report using drillthrough URL. I have added new helper method to pass date instead of InvoiceId and filter datasource on InvoiceDate field. But form is showing all records. For testing purpose, in init() method of form I checked for element.args() 

Common callerRecord;
callerRecord = element.args().record();

if(element.args())
{

info("Some Args");
info(strFmt("Parameter %1",element.args().parm()));
info(strFmt("RecId %1",callerRecord.RecId));
info(strFmt("TableId %1",callerRecord.TableId));
info(strFmt("Table Name %1",tableId2Name(callerRecord.TableId)));
}

element.args().parm() is showing string with required date highlighed in image.

Below is my helper method in DrillThroughCommonHelper class.

I also tried to invoke with hard typed date in the business logic in report design but with no success.

Please guide how can I pass date to form from SSRS report .