FWIW, I've just started using V6I, with most of my work involving animations with dynamic cloth imported from Poser 6 (I have P7 but don't use it anymore since it is awful at cloth sims and the main advantage of better firefly render times is now moot given my shift to V6I). 

What I've discovered is that the dynamic cloth sim sometimes imports and sometimes doesn't.  I haven't done enough testing to know what's causing the cloth sim import failures, but I have discovered that if I want it to work every time, I make sure I do the following steps:

1.  save my PZ3
2.  set up and run the cloth sim(s)
3.  save the PZ3 again

Cloth sim imports properly every time.

I do know that if I move a PZ3 from one directory to another, the cloth sim import usually fails, even if I also move all the associated files, like the dyn and tmp files. 

Also note that I do not use external morphs.  Don't know if that makes a difference, but in case it affects the above solution one way or another...

good luck