Paul has seen the case where a USB keyboard works to configure BIOS settings and it works at the ISOLINUX boot screen, but then stops working once the Network Security Toolkit has booted. This happens if the mbase configuration is chosen as the boot method (or any other configuration which does not include USB support). Paul typically avoids using the mbase configuration in this situation as it doesn't load enough drivers to support a USB keyboard.

So, if you have a USB keyboard, you will not be able to boot the mbase configuration. You must choose one of the other configurations which include the NST_USB option in order to have the necessary drivers loaded to support a USB keyboard. The desktop (which is the default boot), server, and usb configurations all include support for USB keyboards.

If you really need to boot the mbase configuration of the Network Security Toolkit, you may need to find a PS/2 style keyboard (or USB to PS/2 adapter for your keyboard).

If you are feeling adventurous, you could check your BIOS settings to see if there is a parameter which allows your BIOS to emulate a PS/2 keyboard.