The easiest way to do that is to load up as you normaly do. get your figure in, and load the prop. Now, as you already know it is going to go to it's parented location. Then select that item and double click it. you will get a pop up with it's properties. select the set parent button, and select universe, then ok. This will let the normal XYZ translations work again. Then move the prop to the new location, say the left wrist. I use my dials all the time to get this done. Once it is in the spot you like and scaled ti the best fit you like, then select the part of the figure that the item rests on. You'll see in the corner of the poser doc the figure and the part are showing (figure 1 left forarm) then select the prop and double click it. Then select set parent and then roll down the list until you see the part the prop is on (left forarm) select that and it shoudl highlight, then click ok. Then click ok on the properties box. and presto! the prop is now a parented to the left forarm, you may need to re-adjust the prop once it parents. Just remember that all XYZ translations are from the arm in it's default 0 degree pose. From there if you decide to save it in your library, just give it a new name and select yes when it asks if you want it to be a smart prop.