@ragnar: Yes, you could do that, just make sure you do not overwrite any files that Poser needs. However my recommendation would be to copy your Windows runtime to the Mac, remove all windows executables and add it in poser as an external runtime. At least that is how I did it when I switched to Mac. All you have to do then is to re-install/extract any Python scripts into the Poser Runtime Poser8 set up during installation and you should be set. That way you can still use poser while you might be setting up a clean runtime.

@everyone else: I have the same problem as Stevey3d. Just as a test I copied the contents of my Poser Pro runtime into the Poser 8 runtime and even then only a small percentage showed up, so I think that  there is something wrong with the way the runtime contents are displayed, because when I load an older file that was set up in Poser Pro it loads fine, so Poser8 knows were the files are, just does not show them in the library.
Anyway, just my 2 cents on the issue.

   Seb