I find, personally, that if you right click on the sound you have recorded and pull up the sound editor then all you have to do is go to EQ at the top and figure out what frequency the sound is on. (So the little levers that you can move...pull them down one at a time until the hiss stops-leave all the others up and take that one down) that's how I get rid of hiss. I hope this helps you :)
No offense intended, but that's a little like painting someone's portrait with a two inch brush. Sure you'll lessen the hiss, but you'll lose a lot of the good stuff along with it. MAGIX has provided other methods that are a little more precise.