Surely I must have missed something?
Downloaded video of band playing song.
Loaded Video into Proclaim as background and overlaid with words.
No sound from video (it being background I suppose)
Loaded video into quicktime.
Exported Audio as MP4
Loaded MP4 into iTunes
Created MP3 version.
Saved MP3 version
Deleted MP3 version from iTunes.
added saved MP3 version as audio track to the video that I have already playing as a background.
Synced the lot.
Boy! that was convoluted.