10.2.8 and above has support built in for USB 2.0 PCI cards. And they run at high-speed. I have a SIIG 5-port USB 2.0 card in my B&W, natively supported by 10.3.2.
In 10.2.7 and below, you have to install a driver for the card to work in high-speed. USB 2.0 isn't supported by OS 9, either. USB adapter card support (what you found on Apple's site) is only for OS 9 and only for computers without built-in USB.