Non-Linear Analysis - NewtonRaphson

Hi,

I am doing my final year project on finding the optimum pre-stress in cable domes using non linear analysis. I am using the NewtonRaphson node but need to ensure that my structure is being pre-stressed before applying external loads. Is this something that is done automatically by numbering my load cases, or are further steps required?

I currently only have two load cases, initial-strain and a mesh load. 

Thanks in Advance,

Ash