I'm using Stickmount, it shows it has superuser access.
I just looked around in Root Explorer; storage/sdcard0 was read-only. I set it to read/write access. Now I can save a document from Kingsoft to the device, then copy/paste to the USB. Doesn't seem to want to write from Kingsoft directly to the USB.
Its a workaround, but I can live with it...
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