How to render interior scenes with using background picture (outside)

[tibique]

Hello,

 

I have the following problem when using fryrender. I want to render interior scenes. I have read in the manual, that I shall not use environmental lightning, because it needs to pass through glass and the calculations are very slow then. So I turned off the physical sky and set up interior lightning. But I cannot use the bacground image, because the background image cannot be seen through glass (as written in the manual). Is there a way to work this around except for deleting the glass?

 

Thanks