HD multi cam sync

I just recently switched over to shooting in HD. I'm using a Panny HMC150, the latest version of FCP, and have no trouble using the log and transfer window. Once I get my clips transcoded to prores 422, 1920 X 1080, and sync them together as a multiclip, the problem starts. I drag the clip from the viewer to the TL. I double click on the clip to load it into the Canvas, and I make sure it is set to "open" and "volume" only, as I did with SD clips. But when I play the clip on the TL, it will only play in the canvas. If I double click on the clip again, it plays only in the viewer. I need the viewer and the canvas to run at the same time to edit the footage. What am I doing wrong?
MIke

mac os x 10.6.7
2 x 2.8 GHz Quad-Core Intel Xeon
2 GB 800 MHz DDR2 FB-DIMM memory
mac pro