Final Cut: how to playback sequence while capturing video? When you open "log and capture" window, you can't use other FCP windows anymore. How can I listen to already captured video? 

I want to record my solo on top of rhythm which was captured before. I don't want to synchronize videos.  If I just could listen to the first video then everything would be fine. 

I would like to do the same thing as in Logic studio, listen to 3 tracks playing and record a 4th one in real time. 

How can I achieve this in final cut?
As far as I recall, you can't.  I would tape your solo on your camera while playing your time line and then importing that video back into FCP once it's done.