Slightly odd problem which I've had for years and never bothered to query, because there's an easy workaround. But it's annoying so maybe someone can tell me what's going wrong!
Setup is Sibelius Ultimate, Vienna Ensemble Pro, VSL Special Edition libraries (classic VI, not Synchron-ized yet). I have a playback config that includes several VE instances, one for Appassionata strings, one for woodwind, one for brass, and so on. There's also one for solo strings, for the odd occasion when I need them.
I create a score in Sibelius, and in the Instruments dialog I add string parts using "[VSL Appassionata strings]" (from the Vienna house style).
If I notate string parts with technique text "pizz.", the samples from the Solo Strings VE instance are played, instead of the App. Strings.
All other articulations play correctly using the Appassionata patches.
The workaround is simply to go into the Mixer and force Sibelius to use my Appassionata strings instance for the string parts, by clicking on the green-on-black boxes and selecting the correct VE instance. After doing this, the pizz patches from the Appassionata are correctly selected.
Before - solo strings pizz patches are selected:
After - all works correctly. The only difference is that the instance names are no longer in parentheses, indicating that they have been manually selected rather than assigned automatically.
Bizarre, no?
Mike