How to identifie a simulink black box

Hello everybody

I've given a engine Simulink Block (with a compield S-function, so it's a black box) with 8 inputs and 9 outputs... Is there a way to identifie the block with the system identification toolbox if for example I hold 6 inputs as constraints and 8 output as constraints too....so that I have 2 input and 1 output? (Speed and Throttle as Input to get the Resulting Thrust as output) I've already generate some Input-Output Data...but to get a function with polynomial approximation is not working properly.

Thank you very much

Greets

Berkay