jcjeant, methinks hydraulics failure would be a priority message. That strongly suggests that the VS was still attached up to one message time plus some Kentucky windage before the transmissions ended.
We have no real idea where the plane was at that time. The simplest suggestion is that transmissions ceased at the same time the plane ditched. The second simplest is a flameout for all engines, which, I believe, shuts down ACARS. So the plane could have still been a modest distance from its ditching location.
That aside, there is no compelling evidence that the VS was not attached at the time the plane met the ocean's surface and shattered. If someone postulates that a rudder setting somehow caused the VS to shear off they'd best be prepared to describe what the mount points, the clevis joints, that held the VS to the tail would look like in that case and show that they'd look like the damage we saw to the VS and the pieces of joint still attached.
The damage is particularly well suited to explanation via mm43's ditching diagram for the plane. The tail assembly hits the water with its nice wide flat surfaces and gets pushed upwards breaking at the bottom of the fuselage first. That leads to damage to the back end of the VS and rudder as well as a bunged nose on the leading edge where it was against the fuselage. The middle joints broke first then the others followed.
I cannot put together in my mind a scenario that has the VS mounting points come out looking the way we saw them in the pictures posted and in the BEA reports.
VS comes off in flight is not a scenario I can put together with the pictures and come out as a coherent picture.