Room divider wall in vaulted ceiling room

[nibeck]

Home Designer Architect 2024 - Macintosh

 

I have a single room with a 2 story vaulted ceiling. There is a divider wall separating the two sides.

 

Two questions for this layout:

 

1 - How do I keep those divider walls from going up to the ceiling, they are supposed to only be the height of the first floor. 

 

2 - For the Gable wall, how can I turn off the crown molding on just one wall?