I highly reccoment the canopy glue. I believe the stuff I use is made by Pacer Tech (same people that make ZAP CA), and it is white like Todd was talking about. It gives an amazing bond, easy to work with, dries clear, won't fog, cheap, etc...
Polycarbonate is difficult stuff to work with (as far as sticking things to it, painting, etc...). Its impervious to just about everything---but the canopy glue works great on it.