I thought initially that this could be easily solved with Action Sequences on the imported SWF file. Action Sequences will control the visibility, play(), stop() and go to frame, it doesn't stop the audio that has already started playing in the imported SWF.
I worked around this by
- placing an empty frame "0" in my Flash .fla with SoundMixer.stopAll(); in the ActionScript - then reoutput the SWF
- Imported the SWF and then set an ActionSequence to go to Frame 0 and Stop when I exited the state where I wanted my SWF playing
- Also set an ActionSequence to go to Frame 0 and Play when I wanted my SWF to start playing again
See the source .fla and .fxp here: TestingSwfSoundStopStart.zip
Thank you very much, its works very well!