Yeah HUGE relief, so glad I bought the combo of Drivepool and Scanner! Well worth the 'cost of admission'!
Ah ok then, there's 2 enclosures I've been looking at, one is USB3.0 only, the other is USB3.0 and eSATA. The eSATA one seems to have issues with not seeing all the drives on certain chipsets so I'll have to make sure the PCIe card I get is capable.
But that's good to know, as long as WHS can see it, Drivepool can see the pool, everything continues working.