Oops, I take that back. I'm still having problems. My wind choir trills properly now. But, in a separate score for string orchestra, I still cannot get harmonics to play back properly. I did install the SE+ Soundset, and updated the performance Dictionary as told in the help file. I made sure my manual soundset was set up properly, plus I made sure everything in the Sibelius mixer was on the correct channel. But now, not only do the harmonics play the same patch as before, but I can't get anything except the first and second violin sections to play back at all (MIDI channel 1 and 2). The violas, cellos, and basses are not playing a note, even though they work when I hit the "Test" button in the Playback Devices window.
I haven't got a clue what is going on.