Remove Sun from outside

[Eleethesontai]

Hello,

im a newb to both rendering and twilight and im having trouble trying to figure out how to do this. was playing around with a simple room with a wall and a floor. What i am having trouble with is that the back wall that i removed so that i can see the scene allows sunlight in how do i fix this?

Model: https://www.dropbox.com/s/arrcm2tpvnuw3 ... 1.skp?dl=0
Render: https://www.dropbox.com/s/byerhf52776ay ... 1.jpg?dl=0

[Fletch]

Subject: How do I render an invisible wall in Twilight Render?