hello again cyline - glad my post was of use to you.. your solution of finding a split point in the Score Preferences is a good one but is only the first step for general use.
If you sometimes have the Left Hand of a piano part going above C4, or the Right Hand going below then you will have notes on the wrong stave. ( By the way LHS means simply Left Hand Side, ie of the screen where all the boxes are in the Score Editor). But for Piano Part here are a few pointers:
1. Make a blank region in the arrange page, or play something in to the Logic
2. Open Score, and select a Staff Style in the box near the top on the Left Hand Side
3. Open Staff Styles and "duplicate" a Piano Style with your own name say PNO 1
4. Now you are using a multiphonic staff style it will give you the possibility to re-assign the lower stave to a different midi channel.
5. You are now able to use the Voice Separation tool to drop or raise any notes which are in the wrong stave. Also look into the Key Command for swopping a note or selected group of notes + or - 1 channel
Check out illustration:
[IMG]
http://i364.photobucket.com/albums/oo82/dogliege/PianoPart.png[/IMG]