Project audio set to 5.1 surround in Movie Studio 10 HD Platinum. AVCHD 1440 x 1080i video which when rendered for blu-ray in mpeg2 produces a m2v video file and w64 sound file which is then sent to Architect Studio 5. My query is that the audio file is rendered to PCM stereo and this is the only option available in the drop down box. Should AC3 5.1 be available?