As long as you are staying on the plan and not giving up, you will succeed. I know how you feel, I've been having some problems myself, but then, just when you think it will never move...it DOES! okay, one pound, but hey!!! one pound gone is pretty darn good in my book! so hang in there just like you are, you are determined and you will be successfull, I know it.
There is a new South Beach diet book (SB Supercharged) and there was an article in prevention magazine this month about the new supercharged plan. Mostly the article said we need to exercise. It also mentioned interval training so I tried that today by increasing my speed on the treadmil to 4.5 mph for one minute and then back down to get my breath and recover then back up. Im hoping that will help me too.