Hey guys, I?m doing a volumetric lightning effect on the little house i?m making, and I just need an effect similar to light_spot to complete it, thing is that light_spot gives us a circular light spot, and I want it to be retangular, is there a way to do it?

To illustrate: http://img715.imageshack.us/img715/8026/lightw.png

I want a light spot only over the retangle i?ve terribly drawn (lol).

Thanks!