You would first need to identify what surfaces where you hear footfall sounds that you don't like. Like sidewalks, street, tile, etc. Also, is your character female, male, or huge? This is important to know, so that any replacement files are named correctly.
You can do this by running around in zones or missions, but you can also edit your base to have a room full of different surfaces.
With all my delving into sounds, 'Feet' sounds are probably the most numerous. So try to mark down whenever you can, what surfaces you hear the hard-heeled boot sound, that way we can try to catch them all.