How to do a see through fireplace...

[atpgod]

I am currently trying to get my current house under construction (Info On my Blog), I've currently made up these drawings... http://atpictures.home.comcast.net/HouseImages/. I can't for the life of me figure out how to put a fireplace in the wall. There already is a symbol in the library for a multi-sided fireplace. But I can't get the fireplace to show up IN the wall, and being able to see through it.

I could even be okay with a "clear image" on the wall of fireplace logs that I will let me see through to other side of the room.

Can anyone offer up suggestions? You can see the layout of the room here.