I use V-Vocal on X2a without issues -and it's great by the way.
That said, after installing X2a initially I did have a problem with V-Vocal. It was crashing my file every time I tried using it. After speaking with Tech Support I learned they were familiar with folks with this kind of issue and advised the way to correct it is a full uninstall of X2, and then a re-install.
That sounded like a horrible idea.
But Tech Support provided me with the steps for the full uninstall (and I've seen those steps listed in several threads here in the forum).
It was actually pretty painless to do the uninstall and reinstall.
After I did that, I found that everything worked great including V-Vocal. I now use it regularly without issues and appreciate its features.