LHD,
I would suggest that the max. size for an individual image file is 4GB, so Acronis is simply spanning the 10.2 GB it needs to create an image of your disk over 3 files.
In terms of recovery - kill 2 birds with one stone. Buy a second hard disk equal to or larger than your existing HD.
Take out the existing HD and put in the new - now restore your image onto the new one, check it works.
Now you have verified the recovery AND created a mirror disk.
BTW - Have you checked out how you get the image files from your external Freecom HD back to the PC when you have no OS on it? I'm assuming the Freecom HD is connected over USB - but will the USB device be visible when you need it? I rather suspect not, unless Acronis supply a bootable CD that provides USB support.
SD