Are you talking about adding a new or pre-existing staff (perhaps at a smaller size) to another part (which can be done via the Manage Parts dialogue), or are you talking about adding cue notes to an existing instrument's staff?

Thanks for your interest!

I'm talking about adding a cue staff to one bar of an existing instrument's staff.  

Which was explained in your prior request. Why did you ask twice? 

Sorry for the mix-up!

This question was about how to get a cue-staff to appear in a Part, via the way I am creating my parts. I didnt' realize that you were the same person who had answered the first request, and thought I would simply answer the responder's question, without going into too many details. It was only after my reply that I received your helpful reply re. this question.