I have a Band-in-a-Box backing track and the Lush Music arrangement of “I’m Getting Sentimental”, which is supposed to be a proper transcription of the Dorsey arrangement.
Incidentally, we have been through this exercise previously on the forum with lots of suggestions. I'll see if I can find it with a Search function.
Yes, here it is:http://tromboneforum.org/index.php?action=printpage;topic=33577.0
I also have the BiaB trombone sheet in my forum library and so can attach this below. However, it was my transcription of what I needed to see to sound like Dorsey and there was some criticism. But I could send the proper 1st Trombone sheet from the arrangement if you do not already have a copy of the Dorsey part.
I can email you that copy of the trombone part from the arrangement. I could also make you a copy of my backing track that you can play on say a Windows Player - Midi perhaps?
Let me know if any of this would help.