CST-a PEC face on a brick!!

hello,
I have a brick with a 12 dielectric constant, and I want to define a face of this brick as PEC. How can I do this?? I tryed something, but when I made the simulation I get the follwoing message: "Sheet bodies will be ignored in the simulation"!!
thanks to all.

drawing a thin film ,set up it for PEC conductive

If you have PBA turned on you can't use a 2D sheet, in v5 and below.

I believe the PBA method in 2006 can handle 2D sheets.

Added after 7 minutes:

Actually, you're probably better off extruding the face by the trace thickness and assigning it to PEC. The PBA will take care of the thickness so you won't have to have a small cell there.