Might be cheaper/easier to get a paint shop to do it for you..ask around for a few prices.No good slapping the recess full of filler btw,it always cracks.Needs a metal plate welded in
Well as far as i am aware they try to make the majority of it metal so they would cut out a large section of your boot weld it on grind down the welds etc. so it would be minimal filler needed, Paint.
Example: http://www.youtube.com/watch?v=qOy3a1v6Hsk