I can't look at the Poser 8 light sets right now, but here is one thing to note: when you use IDL, light-based ambient occlusion is not used at all for the render - it is automatically disabled.

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)