Firefly is capable of IBL based rendering utilizing HDRI natively. The ProbeLight node is the current (sad) access to this capability. It does not accept hdr files. It does accept IBL values created from hdr files. Steve -- the script is run outside of Poser, in a command line window. It creates a list of values that are then typed into the value params for the probelight node. By hand, lol. This probelight node is then copied to all surface paramters within the scene (copy paste is useful). When doing so, it is generally better to apply it to the alternate diffuse channel. The PMHDRI set up is a fake -- it uses actual lights. To engage this completely, one does not use any of the lights within poser.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)