Which one? There is more than one? Why aren't you asking the vendor of the shield?
have you got any documentation for develop a sketch that is capable to create a connection (serial) between a USB peripheral and arduino.
The communication between the USB shield and the Arduino is NOT via Serial. The communication between the USB Shield and the USB Peripheral is NOT via Serial, either.
....i must only send from arduino, 0x06 character to usb cable (that convert in pure serial) and i must listen what peripheral respond....but libraries are not complete of manual....thanks for help