Well, got that installed without a glitch! Installed a 320Gb SATA disk into it, went thru the setup wizard and it just works!
The only gotcha so far is that the USB ports are at the rear of the unit, and not easily accessible.
Next I'll connect up the IOMega 350GB external USB drive to the NAS200. Don't expect any adverse to happen (just have to re-jig some of the cables around here!)