I don't know specifically about the SR helmets but in general ski helmets are designed to take a large impact: when your head hits the snow, there is typically a very large surface-area of impact as the helmet presses into the snow. Whereas with kayaking, it is typically a point impact. You'll also notice that most kayak helmets are rigid and do not compress as much in an impact while in ski helmets the foam usually compresses permanently upon impact.
So, while an SR helmet is better than nothing, I would personally still use a helmet designed for skiing.
"The world would be a better place if everyone kayaked."-Brad Ludden (Valhalla)
"You only get one chance to run a drop blind."-DD