I've had much better luck with the Sunlite branded pads that say "for steel or alloy" on the pad holder. Once your adjustment is set up, if it still squeals, I'd go to a different pad. I could never quiet down the regular Kool Stops I've tried with chromed steel rims.

Edit - The one Kool Stop pad I've had that worked was the black "John Bull" replacement pad. The rubber on that seemed better suited to steel.