Hmmn, not sure about that one. I would guess probably not, because the reason they are syn free is because the water content within the whole veg helps to fill up your stomach, and takes longer to be broken down during digestion. Also, you would use a whole lot more vegetables to make juice than you would normally eat, thereby consuming a whole lot more calories. I remember a consultant once giving a woman 8 oranges to eat, and another the juice from 8 oranges to drink, to highlight the difference between how many calories you could eat/drink and the difference it had in consumption. The woman who ate the oranges only managed 3 before she was full and had approx 180 calories, whereas the woman who drank the juice had consumed approx 450 calories (based on 8 oranges) and was still hungry.
I would assume that juicing vegetables would probably mean that you're leaving behind the filling content and most of the fibre in the pulp and therefore isn't likely to still be free. When you blend vegetables for soup you're still going to be eating all the vegetable pulp, so it still fills you up.
That's what I would think anyway, just based on the SW principles. (I've been on and off this diet for too long - I've asked too many questions before in the past!!!!)