Sorry about that but i remember that lots of my figures with dynamic dress have  been transformed with spawn morph target option
It because i don't use POser for animation so i delete all  frame except the one i need
So i have tried with all frames and dynamic transformation of the dress prop ;save a pz3 and try to import in C8pro
Result :the prop dress is there but without transformation and V4 is animated
So a dress prop with dynamic modification seems only be imported if you transformed it   with spawm morphes
I remember that with C7 and transposer it was the same situation