MM43,
Sorry, I have to disagree with you on fin and rudder remaining effective at high AoA. In fact the increased sweep coming from the geometric sweep plus the AoA means that the fin and rudder lift curve slopes fall sharply as AoA get large - see Fig9 on the figure. OK, this is obviously a Boeing design, but fifty plus years in aerodynamics tells me that the A330 isn't going to be a mile different. So although the yaw damper was working the rudder pretty hard, I doubt it was really driving anything since at 40 deg AoA it was down to about 1/3 power.
In addition, when a swept wing aircraft gets to that sort of AoA the lateral behaviour changes from a classic dutch roll to something more like a simple roll oscillation. This isn't sudden, and (of course
) the A330 at 30~40 deg AoA lies in the transition zone. But a feature of this change is that the relative phasing of yaw rate and roll rate alters, so it is impossible to say that the yaw damper is driving roll - it is more likely to be lagging it considerably.
Clandestino;
You are right to express caution on using classical unstalled equations to explain AF447 behaviour when stalled, but there are other theories that may throw some light on it - but treat with care! - and they will only give an indication of what might be happening.
Amongst other things there is a little matter of asymmetric shedding of vortices off the forward fuselage at high AoA (see picture), and this can be time variant, so it is a brave man who says he can explain what is happening (or one with a lot more data and computing power than I possess)