Most professional renders are hand painted to some extent (post-worked), so why should you feel guilty for doing the same?

Ignore the purists. The only time you should be restricted to only what the render engine produces, is if you're entering some kind of render contest that doesn't allow post work, or making product renders for a content store and need to show exactly what the item will render. Otherwise, do whatever you need to do to achieve the end results you're looking for. Too much time spent on trying to get the perfect render just results in wasted time that could have been spent on the next image in the sequence, or the next project. Poser is just a tool. Some people only use it as a reference for hand drawing their poses in perspective and never bother with materials or renders.

This webinar is about an artist that used poser and photoshop to produce a graphic novel called Anomaly, using basically the exact process you describe. https://www.youtube.com/watch?v=eqDY9_dYOVY