Yes. It's possible. I wonder where you find the quoted code, because I've been using [0;0;0] format not knowing it's OK the other way, too.
For these vector variables or parameters, you may functions like sum and dot to perform vector manipulations. You can also use syntax like V(1) or V(3:end) to define equations on specific components. If I manage to find more complete documentation on this, I'll post again.
Whenever I'm not sure how I should write the equations for the vector variables, I found it convenient to try things out in PS first. PS constant can be vectors, too. So I can write blocks in PS domain and have a scope to look at them. If things all behave as expected, I would implement the equations in the actual domain.
Hope this helps.