I used Au CS6 for quite some time. The Mix/WavePad equivalent I use it the Hard Limiter preset on the Compressor. I found the preset for the Hard or Soft limiters to be adequate, providing things weren't too loud already when going into the processor. Otherwise I would say reduce the overall volume first?
I'm a "trial & error" kind of engineer so if you want me to take a crack at anything send me a link to the audio & what you want. I'll see if I can figure it out.