simulation of ferrites by cst mws or hfss?

Hi my friends.
I want to simulate a ferrite device by a simulator.
it seems that the results of cst mws is not real.
I can't simulate ferrite with hfss.
i don't know if the simulation of ferrite devices by hfss match with practical results or not.
please give me an idea about the simulation of ferrite devices that can be match with practical results.
please help me ,please...

I have simulated a ferrite isolator in CST and the results were quite accurate. So I think it is possible:D

could you give more detailed about your mode