http://sn.1w6.org/file/mk-20151024T123817-wqsqj6e.html
OK, most important step done: both (brand-new) HDs installed in the RAID box, attached by eSATA, and a refresh in GParteEd detects the device. Created a Swap partition and a 'home' partition. #phew (I nearly panicked because a drive installed in my external enclosure was not recognized at all - but the RAID box has no complaints.)