connect data drive to Cisco Explorer 8642HDC

I had tried to do this several years ago but at that time the Cisco firmware/Cox software appeared to not allow the drive to be used. Recently I saw a set of instructions from another post on this forum (related to a slightly different STB):

Connect the external drive to the SA 8240HDC as follows:

1. Turn off & UNPLUG power to the SA 8240HDC box
2. Install an eSATA cable into the port on the SA 8240HDC box
3. Connect the eSATA cable to the SATA drive
4. Plug in the power plug for the SA 8240HDC and wait until it completes rebooting
5. Plug in power for the SATA drive and turn on the power
6. It may take a moment, but an on-screen prompt will appear stating when the external drive has been detected
7. Press the yellow triangle button on the remote to permit formatting of the external drive

So, I followed these instructions to connect my old WD DVR Extender sata 1TB drive. I did get the message referred to in step 6 and pressed the yellow triangle (A) on the remote, but there was no response. The onscreen message remained. After a couple of minutes the message disappeared, but in looking at the DVR list, there was no change in the free/used space graphic (it still showed 97%). However after I powered down the STB and powered it on again, the DVR list now showed 31% used, 69% free which would be correct as the new drive is twice the size of the builtin HDD.

My question is: how can I confirm that the added drive is properly formatted? (or is it obvious because of the DVR usage graphic). I am able to record and view/delete etc programs but not sure if everything is ok.