I suspect Poser's problem with Water is the same as its' with Chrome, in comparison to Vue/Bryce.  In Vue/Bryce there really is a whole 3D world for a reflective object to interact with, but Poser does'nt have this luxury, it only has blank space, really.

Unless, you can figure out how this works(Please let me know if you can!)

Alternatively, you may want to look up bagginsbill over here, and tell him I said hi!

=  )