Invisible objects renderer disable? How to stop this?

Hi,

I have a GameObject that casts a shadow on the floor by sending vertices to the shading pipeline. But when that object becomes out of sight, even if the shadow is on sight, the object stops rendering, and so, the shadow disappears also.

So my question is: Is there a way to make object not stop rendering even if it is not visble by the fustrum?

Thanks!