You can hit Ctrl-A to select all and drag everything up or down at the same time in V-vocal.
The only problem you'll run in to is how well V-vocal detects the pitch variations. It may not be able to detect every spot that's out of tune, so when you make your global adjustment, some notes may be left out.
There is a
free Auto-Pitch correction VST put out by Melda that I've been using instead of V-vocal. You can adjust the sensitivity of it and how fast the pitch corrections happen. It's a great little plug for free.
V-vocal is geared more toward precision correction of small clips rather than a whole track like you are trying to do.
Good luck!
Bub.