I am working on an opera, and since Vienna Instruments has no male voices, I have been using Sibelius 6.1's Sibelius Play for the voices, and VE for the instruments. I noticed that the soft dynamics on Sibelius Play were much softer, so I tried the option mentioned on another post and set in VE I set both Expression and Velocity Crossfade to use controller CC11. Now the dynamics match much better. I'll have to see if this approach creates unforseen issues, but it did solve the mismatch between Vienna Ensemble dynamics and Sibelius Play. (I have felt before that Sibelius's default dynamic values might be a bit exaggerated, but if I decide to adjust those values I can do it in the playback dictionary.)
I would also like to know if Vienna Ensemble Pro can be called up from inside Sibelius 6.1. If so, it looks like something I should purchase.