Getting area/point light to diffuse against dark glass.

[banditcloud]

Hello,

I am working on a render for a wall-mounted lighting product and I can't seem to make the light behave the way I want it to.

Essentially I have this wooden box and its front is covered by a dark see-through acrylic/glass panel. Behind this panel are RGB LEDs that should diffuse through the panel to create a spotty rainbow effect.

But whenever I try to re-create this in KS I can't seem to get the light to diffuse through the glass without having the entire interior show through.

I attached a screenshot of the problem at hand and a Photoshop edit of what it should look like.