Currently Being ModeratedApr 23, 2013 6:28 AM (in response to deweyk)
You can do that in Final Cut Pro X, but not in iMovie.
A good workaround in iMovie is to line up the WAV file with your video clip. Then use SHARE/EXPORT USING QUICKTIME/Movie to QuickTime Movie/Options/Video Options/Compression/Apple Intermediate Codec. Save this file to a place you can find it. Then import it back into iMovie using FILE/IMPORT MOVIE...