What option did you use to send your files over? There's two "paradigms" for editing in Audition from within Premiere. The first is editing of specific assets or clips. In this case, you select one or more clips and choose Edit > Edit in Adobe Audition > Edit Clip which will perform a render & replace operation, then open the new, linked files in Audition. Any change you make to these files in Audition will be reflected in the corresponding Premiere clip. This is generally the mode used when you want to perform Noise Reduction or add effects to specific clips.
The other paradigm is editing the entirety of the sequence. This method creates a new session in Audition that mirrors your current Premiere timeline, even rendering a preview video. Here, you can apply edits to any clip in the timeline within Audition, re-record portions, add new audio, and mix and master the session, sending back rendered stems to Premiere.
Audition doesn't emulate the "project" format of Premiere, so the Files panel is less of an organizational tool than a collection of the raw assets in a timeline. We are exploring how the "bin" concept that Pr and AE use might be applied, but historically there is a definite distinction between the two workflows.
