Question about electric wall in cst

Dear all,
Could anyone has experience using cst explain me , how to make magnetic and electric wall in such a case.
I make single patch and want to investigate infinite sequence array by using mirror concept.
Put E wall in front of it and behind it, and H wall on the right side and left side. But in cst we cant make parallel symetric plane to investigate radiation pattern.

we get message, "parallel symetric plane, no farfield calculation posible"

thank in advance.