You know,...I was sure I was using IBL in superfly in Poser 12 and Poser 13 before the update that I just installed yesterday. So I went back to Poser 12 and tested it. And it worked. Here's a quick test. I have 1 light. An IBL. I set the intensity to 300% and then I rendered in superfly and this was the result. I did have to hide the ground sphere or else I would just get a black screen. 

There is also a video on youtube created by Renderostiy and in the video, he does exactly what I did. In fact I learned to do this from that video. And I was doing this in Poser 13 too until yesterday.

So maybe there's something in the latest building besides the ground that is blocking the light. Or maybe it was working and it wasn't suppose to be working. But it was. I did it many times. Until yesterday. And I can still do it in Poser 12.

But I will try to use the HDRI method. (I actually thought IBL was Poser's version of HDRI lighting.)

I actually did a render today using an HDRI after I set it up from a tutorial I found online. The HDRI showed in the preview, but it did not render. And the HDRI was blurry. Is there a way to make it show in the render and not be blurry?

I did buy those products Rhia474 mentioned above. I will try them when I get them installed.