Composite security for tradestaion

I am using tradstaion 8.7 for real time trading.I am getting getting the real time data to through the global server which is getting data from the Meta RT.I desire to create a composite security i.e a security which is some mathematical combination of two [login to view URL] i am talking about mathematical combination I mean that all the mathematical operations should be available to me like exponent, log, etc ( and not just the simple plus, minus, dived and multiply).