Non tonal scores
I want to write a work for Bb trumpet and piano, but non tonal. When I select the instruments, I had to select "C major" as key signature, not for tonal reasons but for non tonal objectives. When I choose the Bb trumpet this always shows D major as key signature, but I want the Bb trumpet without key signature because it is a non tonal work.
How can I get the Bb trumpet without D major key signature? Is it possible?