multicam editing codec

I had a previuos post about editing hdv in PrPRo CS5.5
The hdv footage doesn't perform well enough for my Mac Book Pro quad core. The suggestion I got was try converting my HDV to a 720P quicktime apple prores, and it works great. It even works great converted to 1080P pro res.
Problem-when I import the audio mix recorded on multi track
the pro res clips have a higher pitch and play faster, so with in 2 seconds of playback they are noticably out of sync. If I add the audio clip to the original HDV seq it stays in sync.
I have tried DVCPRO HD and its also plays faster. I have tried pass thru and changing the audio to 48K PCM. I have also tried converting the 48k wave file to Pro Res and it stays with the original speed.
How can I keep the encoder from changing the video clip speed?
I have made my sequence tests with (New sequence from clip)to make sure the seq is matching the footage. What is going on in the conversion process HDV-Pro res?
I have also get the same results in FC using compressor.
what am I missing?

Alan Stephens