Capturing sql query result set single value in Project Parameter in SSIS 2012

Hi,

I have a PROJECT parameter "flag" in SSIS 2012. I want to assign the value for it at the run time from the result set of a query.

IF EXISTS(SELECT 1 from TABLE)

SELECT 1

ELSE

SELECT 0

this 1 or 0 should be assigned to above project parameter "flag". I know i is easy if "flag" is a variable. But its a project parameter. 

please help.

Porus