Generally, when you slice the return, it's from a tactical viewpoint something akin to Federer. You slice it because it comes down very fast on the other side to give yourself time to recover and reset the point. That's mostly how he got rid of Roddick. Unless you have godly hands, you're not going to chip and charge on returns. I'd favor a well struck return with better angles (long DTL, cross-court/inside-out with sharp angles) that put your opponent in difficulty, forces him to try a slice to recover or a lob, then finish at net rather than "pure" chip 'n charge. As for the return, ask this guy some advices, cuz' I'm not a coach.