Apple Final Cut Express 4 - Manual (Page 452)

452 Part VI Rough Editing
4 Drag the clip in the Viewer to the Overwrite section of the Edit Overlay in the Canvas.
The resulting edit looks like this:
The audio precedes the video and begins at the sequence In point.
Example: Split Edit in the Viewer and a Single Split Edit Point
in the Canvas
If you set up a split edit in the Viewer and set a single split edit point in the Canvas or
Timeline, Final Cut Express matches the appropriate split edit point in the Timeline to
the corresponding audio or video split edit point in the Viewer; audio to audio, or video
to video. The other, overlapping media extends before or after this edit point as
necessary. This method can be used to backtime a split edit, as well.
1 Set up a split edit in the Viewer, with the audio In point preceding the video In point.
2 Set an Out point in your clip in the Viewer.
The resulting edit points
look like this.