Fluid Scenario Creation - Problem with Turbulence Model

During CFD simulation in fluid scenario creation app I need to put Langtry-Menter 4-equation Transitional SST Model or γ − Reθ - SST model to solve the problem. But in 3DEXP, I have only 3 default turbulence model which is shown in the image given below.

How do I add the required turbulence model?