Railworks America

Howdy, I'm new here... haven't played a train sim since around 2005 (MSTS) and saw Train Simulator 2014 for $20 at Target and figured I would give it a try. Awesome so far, and I love that the controls are basically like MSTS. However some of the sounds were sub-par in my opinion, so I wanted to change out some of the locomotive sounds. My question is, is it possible to have different sounds, like horn, brake, etc than the outside sound? I followed the custom sound guide, and was successful, but I can't find any way to make different sounds for the cab.