How to fix underscan problem with footage

I am trying to help a friend fix a problem with some footage he shot. A client was standing in front of a painted matte. The footage was shot,(and cannot be re-shot) and once back in the studio he found that a the edge of the matte that is not painted is showing up beyond the TV safe area. It can be seen on a computer screen and if shown thru a projector. The viewfinder of his camcorder did not show this problem.
So how can we fix it? It is a narrow band of white on the left side of the screen. The problem is that part of some leaves cross over it and out of frame. We have tried just simply scaling it up to get beyond the white edge but the picture quality begins to degrade. We have to fix this using FCP since that is all that is available to us. The clip is fairly long so we probably won't have the time to fix it in Photoshop.
Any help is greatly appreciated.
He is using FCP4.5 on a dual processor G5.


The cropping would leave a black bar. Something I was thinking about doing has cropping involved. I thought about duplicating the clip and stacking it over the original clip. Then crop it as suggested and then scaling the clip underneath and apply a Gausian blur. This would eliminate the white edge. Problem is, I have a hard line where the cropping took place. If there was some way to just feather the left edge of the crop.
My friend thinks some type of masking needs to take place where we could just re-color the white bar but as of yet we haven't discovered how to go about it.
Thanks for the suggestion,