Aha! I sussed it! Poser writes two files. I believe one of them is the morph info. If you go into Edit/General preferences/Misc (in poser) and UN-check "Use external binary morph targets"  it writes everything to one file. If you import that into Vue... all is sweetness and light. Whooo Hooo! The cloak looks fine - same as in poser.

Why does it have that option of writing one or two files? Anyone know?