This is interesting. I have aglows in yellow attached to spot in sphere with cast shadows. Sphere is 100% trans no shadow. Cube no shadow. Spot is blue aglows is yellow. More light appears to pass thru cube w/ no cast shadows.If I turn cast shadows on the big sphere the light is in tho the light stops. (I agree LCBoliou, I suggested also...they said they could add this.)

No need to think outside the box....
    Just make it invisible.