You could certainly "Open in Audition" CS3 with Premiere CS5 and CS5.5, but as I recall it was limited to either a single clip or a sequence?
Where the "Open in Audition" does not work is with an Audition version number lower than the Premiere version.
I presume you do mean Au3 and not AU CS3.
Many audio buffs still go back to Au3 for some operations, and there is a way in Au3 to use the Audition Interchange files created by Pr CS6, although it is a little more trouble. After completing the Edit in Audition operation for the Pr sequence, go to Au3, open a multitrack view, and then point File/Import at the appropriate Interchange folder to see the extracted files.
The feature you're looking for, the back and forth between PP and AU, will likely require Audition from CS6.
Thank you for all of your suggestions. all helpful.
Sal: yes, I do mean Au3. I'll have another go at importing and see what happens.
Jim: That was what I feared! I'd better start saving
Many thanks folks.
After importing the audio and video files into Au3 from the Interchange folder, the hard part is to synch them up in the multitrack window. I tried using clip markers, but they don't seem to transport, so I manually match the positions of the clips in the Pr timeline.
If you are all done editing the video in Pr, be sure to check the export video box in Pr and import the rendered avi file into Au3 along with the audio, because Au3 has a feature that the later Au versions do not yet have, the ability to export to video with the edited audio. This operation uses the rendered avi file as is, adds the edited audio, and saves a round trip back to Pr.