installing a UPS on a sun workstation

Has anyone ever setup the APC powerchute (business edition agent) software, using a USB drive on any solaris machines?

We installed the software, and it doesnt seem to be giving the option for a /dev/usb device, it only gives options of /ttya, ttyb etc...

anyone ever done this with a USB? or should i try the serial route seeing it is at least giving me those options.