I don't think it's possible to save the videos permanantly on the hardrive but I believe you can bring them back up all season long. Mlb.com has a free highlights of the game section. You can find all the great homerun calls of the season by Hawk there.
By the way the homerun against Guardado was on July 2nd if anyone wants to look it up.
I can use my sound recorder to record the call, but not the video.