SSD Tier is useless on ReadyNAS 4312

It is possible to add internal SSDs for the new SSD tiering feature. Read below for how I accomplished it. I'm not going to run my NAS this way in production though because I'm worried that a future update from Netgear will break everything. I'll wait until this is an officially supported feature. But it should prove to Netgear that it's simply a matter of adding a little more logic to the GUI.

1. You can have whatever RAID you want. I'm assuming you've filled all 12 slots on the 4312 with regular hard drives like you're supposed to.
2. Power down your NAS. Unplug the power. Open it up. Remove the CPU fan hood to reveal the tray and 2 SATA ports.
3. Remove any 2 of your hard-drives from the front bays.
4. Using 2 SATA cables, connect them to the SATA ports found under the CPU fan hood. And of course, hook them up to the SATA power connectors.
5. In the 2 empty bays, plug in your 2 SSDs that you want to use for metadata tiering.
6. Plug in power to turn the NAS back on. You can't really close up the case. Let's move quickly so this thing doesn't get too hot.
7. Using the web UI, select the two SSDs from the "Volumes" screen. Click the "Add Tier" button on the left side.
8. Confirm that you have a second tier. You'll find that your two hard-drives don't show up, but the RAID is still just fine. Power down again like in step 2.
9. Remove the SSDs
10. Remove the hard-drives
11. Put the hard-drives back in their respective bays. Plug your SSDs into the internal ports now. The tray below the CPU fan hood comes out and you can bolt 2 2.5" drives to it.
12. Once everything is wired back up and looks good, close up your NAS, power it back on, and behold you still have your RAID array and also now have a RAID 1 of metadata SSDs.

Again, this is just to prove that internally, everything about this seems to be supported. It's just this Mickey Mouse Netgear web interface GUI has no idea how to display the two internal drives. Everything about the web interface seems hardwired to think there can only be 12 drives and those drives absolutely must be in the hot-swap bays in the front.