Empty scene ignores manual RenderQueue additions

[WilliamKappler]

This is probably a simple issue;

I'm injecting some custom renderable implementations into the RenderQueue directly. This all works fine, but only if at least one object (manual/entity/etc.) has been added to the scene manager. If I don't create at least one other object and put it into the scene manager, nothing I add to the RenderQueue via addRenderable() is actually rendered. renderQueueStarted() is getting called, so I don't really know why it would be ignoring what I am putting into it.

Is there a way to ensure things added manually to the RenderQueue are drawn even with an empty scene?

My system is based on Ogre's Overlay system, but I couldn't find anything the overlay system was doing that I am not with regards to this; the overlay system doesn't seem to have this problem.