i used following Expression in Integer values expression shap
(DT_WSTR, 4) YEAR( @[User::StartDate] ) + Right("0"+ (DT_WSTR, 2) MONTH( @[User::StartDate] ) ,2) + Right("0"+ (DT_WSTR, 2) DAY( @[User::StartDate] ) ,2)
It convert the date into integer like 20120229