External HardDrive for New WholeHome DVR Cisco 9865

For a millenium now, that I have been with Cox Cable, I have been attaching an external Hard drive to the DVR (with an eSata cord) to expand the space for saved programs, and have never had a problem.

When these new multi-room 'connected' whole house DVR's came out, I had asked if I would be able to continue to use an external hard drive to expand the available space as I always have.

They said "Yes, Absolutely you can."

But yet, here I am, trying to connect the same external hard drive successfully to my Cox Cable Cisco 9865 DVR . . . and Failing.

I have called and spoken with the Techs at Cox Cable, they really had no idea about the capability of this DVR nor which kind or how to connect it properly to the DVR.  They said to call Cisco.  So I did.

Upon calling Cisco, they told me that they do not know specifics to any DVR in particular that Cox Cable is using, but that Cox Cable was trained and informed on these DVR models that they are using.

QUESTION : Has anyone using the Cisco 9865 Whole House DVR system box, successfully attached an external Hard Drive to increase storage space ?

And if so, what kind of Hard drive is it ?  Brand, Model, Size, etc.       Thank you