Outside the window?

In our shots, we have a few that we can see the outside in, so i needed to come up with a way of showing the outside (sky) in these shots. After some trial and error, using a S&S system, i opted not to use it, because it effected everything in the scene, and there was no way to block it off so that just a horizon showed up without effecting the lighting we had already done on the inside of the building. I chose a more sensible approach of creating an image plane, and applying a texture that you can see below to it. I then evenly lit it with a light, and placed it appropriately in the scene, to give the simulated effect that the building had an outside to it.