I'm not so sure. I think it's just a different model of Kihraxz Fighter.
http://starwars.wikia.com/wiki/Kihraxz_assault_fighter?file=Kihraxzvariations.jpg
Isn't the Vaksai just a heavily modified Khirasz anyway? That's the whole point of the Khirasz in-canon (well, not really canon anymore). It was heavily modifiable. You end up with different Khirasz that look very different from each other.
I hope they latter do an aces type pack that plays into the modification aspect of S&V. Giving more options to this and the M3A, perhaps.
Oh yes. You're right. I didn't read the Vaksai page close enough.