Have you got the device vendor and product ID in all the sections mentioned in the CyUSB.pdf.
You could try changing the product id in the cyfxbulklpdscr.c descriptor file from 0xF0 to 0xF3. That way the device will enumerate as the Cypress Bootloader and from your description the driver for this loads correctly. If the device enumerates okay then you know the problem is in the inf file. If not then it looks like a firmware or programming problem.