Hi!
I have a similar issue. Normal transposition is no problem but changing the octave of playback.
Case:
When writing a tuba part in bass-clef and later altering it to the key of Eb and treble clef, I have to transpose it up two octaves for it to be notated right. Then during playback it of course sounds two octaves too high.
Is it possible to make the playback of this specific staff to be two octaves lower than notated?
I thought of using two layers (or staffs) where one is notated right and muted and the other is in the right octave, but invisible. But I hope there is an easier way to do this.
I do most my writing for British style brass bands, where every instrument (except bass trombone) is in treble clef. So this would be very useful for also the trombones, baritones and euphoniums.
Hope some of you guys have had more luck with this issue and care to share

Thanks in advance!!
- Christian