Keeping the weight off is just as hard as losing it to start with, and the period of coming off a VLCD such as exante is critical that you increase your food consumption slowly. Understand what your base metabolic rate is, and work on that to work out how many calories you need to maintain. Here is a link to a BMR calculator
BMR Calculator
As you lose more weight your BMR changes, mine is currently 1333. What that means is that I will use up 1333 calories a day to stay the same weight if I were very inactive (pretty much me lol). Activety will increase the amount of calories you can consume of course, as will your muscle mass, so exercise is important whilst you lose weight to maintain and increase your muscle level. Having said that, personally I havnt worried too much about it, but what it means is that to maintain, im pretty much on 1300 cals a day. I know that if I go over 1300 a day my weight goes up. Its hard to come to terms with such a low daily amount but i spend my calories wisely on good nutrionally sound food and cut out the crap food.
On exante you are on 3 meal replacements a day, cut down to 2 plus a meal then 1 plus 2 meals. The exante site gives guidlines I beleive. The most important thing to understand though, and has been my experience with maintaining, that you have to take things slowly. My food intake now isnt much more than it was when i was losing, and thats how it will have to stay if i want to keep the weight off.