color correct them to background, try color correction curves.
lightwrap color changes around edges, blur inner edges for light scattering, slowly fade edges transparently for lightwrap.
keylight can't do any of those things because it sucks. that's why its free. you can buy primatte keyer or ultimatte or something else usefull. google expensive keyers.
you also have the option of using your existing keys and merge them into my ae project which has those features setup from procedural mattes.
ae cs5.5 aep
http://f1.creativecow.net/7088/7088