If you plug it into a Windows box, does it appear like a normal removable USB drive? Or, does it appear as some special device that can only be accessed via special Sony software?
If the former (USB mass storage device), then you should see it mentioned in dmesg output when you plug it into the FreeBSD box, along with a device node like /dev/da1. Try to mount that like any other USB stick and you should get the partitions to appear as /dev/da1s1 or similar. And you should be able to mount that and copy files to it like any other USB stick.
If the latter, you're probably SoL.