Scaling a Spot Lamp in Blender 2.5

I’m trying to create the effect of a narrow band of light, backlighting some text, like this:

I’ve tried using a spot lamp, check Show Cone; under Spot Shape, and then changing the scale property. While the shape of the light cone changes as expected in the modeling view, it doesn’t seem to have any effect in the rendered image (the cone is still circular).

Is this the right way to achieve this effect and what am I missing? Thanks!

i would go about it in a different way.
are you ok with the compositor? try using glow nodes and texture nodes with a semi-transparent tube set to emit.
if you don’t know what im on about ill explain more.

So far I’ve only used the object modeler and video editor (sequencer). A little more detail to get me started would be much appreciated :).