Well that's a bit more difficult then. lol.
I can't remember what those shields look like. If you like the new shields better maybe just buy a couple of sprues of them?
Basically I used extreme highlighting on the shields. Works on most things quite nicely. Basically it goes dark colour, outline/line bright version of dark colour. So enchanted blue/ice blue, red gore/blood red, dark angels green/scorpion green would allo be good combo's.