I believe that this is only a feature of Audition, not Soundbooth. Soundbooth was made for ease of use for those not necessarily into the pro DAW world. Editors, motion graphic artists, those wanting a pretty robust feature set without the learning curve of a true DAW. Audition has replaced Soundbooth as of CS5.5, so that's a good thing for those upgrading. It may not help you out if you're not on the upgrade trail.
Here's a post from Adobe - near the bottom it's clarified: