Yup, that's standard autostick functionality...now what's cool is that with a minor retrofit, you can add shifter paddles to your steering wheel! Man, I did that with my 300C SRT8 and love that mod!
As far the radio pause (and I think you are talking about a CD track, yes?) you can turn off then turn back on the head unit to pause a song but I haven't seen a "Pause" button on that head unit so I'm pretty sure this would be your only option.
As far as muting CD or radio audio, do you have steering wheel controls for the audio? If so, just push the - button and down goes the volume until you push the + button. Or, just rotate the volume knob to the left.
Now, if there's another audio function you want to mute, post up what that is. I was able to figure out how to turn down the NAV function prompts and change it from what I call the NAVBitch voice to simple tones on my REC/NAV head unit.