You could force carbonate it like some people do with their keg beers, however that requires some additional equipment and money. I'm sure the rec.crafts.brewing types know more about force carbonating than me!
If you want to, you could carbonate it in the traditional method and then add some sugar when you drink it to bring the sweetness back... or using non fermentable sugars is another option, but I know nothing about that really. HTH