I dunno how to fake GI in early poser versions, other than the fake GI infinite light sets like the "render upgrade" set shown in the attached image, or use a bright image with IBL and no AO, to avoid the dark areas that most folks actually wanna see in renders. for GI, I would just use carrara instead. it's very easy in that, and most other modeller apps. if HDRI works in P7, then try that, as that technique should be far more realistic than ordinary IBL.