Would building a crescent shaped habitat work if you didn't want to go all the way?
Edit: I'm asking if this would be enough to provide artificial gravity, sorry not not being clear about it.
Like most large asteroids, Vesta is held together by its own gravity, even if it's not held strongly enough to put it into hydrostatic equilibrium. As a result, if Vesta spun fast enough that it could provide a spin gravity at any point in its interior higher than its surface gravity, the centripetal acceleration provided by its own gravity would not be enough to hold it together, and the asteroid would come apart.
In other words, you'll get higher gravity by putting your habitat on the surface.