CST - PCB Studio, about the port define.

Hi, experts:

In CST Studio Suite ​​​​​​​ PCBS, I select 2 net for SI analysis, but here are no options for me to setup the reference pin/plane. In my picture below right side, the reference pin to my signal should be PIN4(GND pin), but when I view the meshes, I see pin 4 and its connecting metals are not in meshing field. Does that mean: the software assumes the ground plane below the signal?

Then I export the PCB file to MWS, the port are set up automatically, in my picture below right side,. This time the port are exactly what I want: Signals are referenced to pin 4. (By the way, is there a way I can setup the port like the automatical importing/exporting?)