Sure, check my previous posts. There's some commands you can enter into a shell if you have a serial connection to the Wiz, or a script you can run otherwise.
(If you want the full function - eg, screen showing usb is connected, press x, etc, then there's an executable on the nand you'll have to run. I think it's in /usr/gp2x with a quite self-explanatory name)
depending on what your trying to place on the usb port. Of course, you should umount the appropriate device first, or corruption is possible. When your finished, remove the modules from memory and remount in the appropriate place.