[Finale] How to get partial slash, partial regular notation?

[Blueyedtam64]

My understanding is I am supposed to use "Staff attributes" to convert part of a staff from regular to slash notation, or vice versa. I must first select the measures I want to convert, at then select the notation choice. At least that's my understanding.

In one of the stupid little things it does, it converts the whole thing to slash or regular. How do I make it only convert part of the staff?