I'm using VE Pro with OS X Lion and Sibelius 7. I use the Soundsets from the user area here. Updates are all recent.
The issue with App Strings I, is that I can't get many of the articulations to work properly, especially trills lately. I copied the Sounds folder over from the Sib 6 folder to the new Sib 7 Sounds folder. The Concert Strings + articualtions appear to be working properly in Sib 7.
I think I know how to setup the Soundsets in Sibelius, but I'm at a loss as to what I need to do to make App work again. It used to work in Sib 6.
I've gone through the Optimizing document again, and don't see anything to help the situation.
I hope you can point me in the right direction.