Non-symmetric S-parameter in HFSS

Hi,

I am trying to design a structure where I need to add some non-symmetric s parameters. However, HFSS is automatically converting it into symmetric. What should I do in this case.

In the structure, I have created circuit port and add snp file which is not symmetric. but HFSS is automatically converting this into symmetric. In this case what should I do?

Swadesh