Hi, Mark:

I never thought of putting the gliss'ed notes onto a hidden track! That'll do it.

However, as you suggest, the optimal approach is "intelligent" glissandii/portamentii markings, as you've done so well with ornaments and grace notes. I don't think you could have auto-transcription of them though, as it might be very difficult for Composer to tell the difference between a fast 32nd note run and performed glissando.

I've been challenged by one of the members of the pit band for my current show to write some Dixieland stuff, so trombone portamento may be an important feature for me for a while.