Defining port 'inside' substrate in HFSS

How can I define lumped port inside the substrate ? We always work with the ports that lie at the edges of the substrate. But I need to define a lumped port that lies at some point inside the substrate, how can I do that? I will appreciate quick response.

Hi.
at first i should know ,what is your design exactly,and then help you.
Good Luck

You can see the attached figure. I have explained the problem in detail.You can see that port has been defined somewhere in between the substrate.To do this , do I have to create a hole in the substrate to make space for the 'port ' ?

can you please respond to my problem. I will be thankful.