Sounds ok. I haven't done one with DME but I know that Mike's Hard Lemonade is a malt product.
I have a super long thread around here on the problems encountered when fermenting lemonade. If you do a search for "hard lemonade", you'll find it. Anyway, the jist of it is that lemonade can be a real bugger to get started. It's best to make a starter, with some super diluted must (just dilute your made up must with water) and some sugar until that gets going and then keep adding a little more must to it until it really takes off. Only then should you pitch it into the lemonade must. It was definitely the toughest ferment I ever had, and I really babied it to get it going and keep it going. I'll also suggest some yeast nutrient in it.
Edit- here's one thread to start with. http://www.homebrewtalk.com/showthre...light=lemonade