Just checked with the p4 nude woman and the poser original clothing, most of it fits if you make sure its conformed, ie either drag and drop it onto the figure or just double click to load it into the scene then right click on it and choose the conform option.

The catsuit looks at first as if it doesn't fit. What you must do for this is first select the p4 nude woman and then from the figure menu zero the figure. The catsuit then fits, although there is some "poke through". (This is when you can see parts of the body through the clothing.) This can be fixed by either turning the relevant body part invisible, which works if the whole of that body part is covered by clothing, or by using the morph brush, which I doubt you played with yet.