It's very difficult for carbs to be directly converted to fat. For someone who performs high intensity activity several times per week, you should not be cutting carbs, especially if you're trying to put on muscle.
I think the first step for you is to figure out what you really want to do. It's very difficult to put on muscle and lose fat simultaneously, so I would say choose one or the other. Also, keep in mind that putting on muscle will make you look more muscular, which should improve your overall appearance, even if you still have a bit of belly fat.
So, if you're trying to put on muscle, don't cut the carbs.