Writing to a USB device on ConnectCore9c

We are evaluating your ConnectCore9c board for use in our next generation product and we need to be able to make TCP/IP calls, write to the serial port and do File I/O with a USB device. I see sample apps for the first two requirements but I am not sure how to write to a USB device. Do you have any sample programs (or have I overlooked one that I already have) or instructions on how to do this? Thanks, Mike Dixon Senior Software Engineer CTES, L.P. mdixon@ctes.com