Okay, I just looked at Ryan's and Simon's items as installed from the legacy content disk and I see why you are having problems with the hair.  In both cases, we are dealing with dynamic hair, a prop hair which response to the character's movements and gravity or wind force.  And usually dynamic hair is smartpropped, meaning when you load it into the scene with your model, it immediately affixes itself to the head it was made for.

The other type of hair is conforming hair, which is rigged to fit particular models and have morph dials built in to change its appearance or style.  These are commonly found under the Figures category of your Poser Library.  Unfortunately, neither Ryan nor Simon have conforming hair as legacy content.  But there are work arounds.

Edit: Give me another sec.  I'm setting up screencaps.