ReadyNAS 104 / APC Back-UPS BE550G/BE700G sanity check

Hi all,

I'm looking for a sanity check before I order a UPS for my RN104.  I'm looking at one of these APC models:

http://www.amazon.co.uk/dp/B002RXED6A

Not the 400 as it seems to not have USB connectivity; the 550 is, I think, enough for the ReadyNAS, but the 700 isn't much more expensive so it's a toss-up at the moment. What I want to be sure of is whether it'll work, and shut down the NAS!

I'm running OS version 6.4.0, and looked at the UPS section of the power settings, but it seemed to only let me add SNMP or Remote UPS. That made me worry that the direct USB connection wouldn't be supported -- is it unsupported, or is it simply not visible until the UPS is connected?

Can anybody reassure me?

Thanks,

Steve

PS I also looked at this cheaper CyberPower model, but since it only has kettle sockets I expect it'll work out more expensive in the long run to buy adapters...