eSata expansion with an already upgraded S3

Since there are over 300 pages of posts in the Sticky section concerning expansion for an S3, I thought it would be easier to just make a new post about my question.

I recently upgraded an S3 (OLED) TiVo with a 500GB Western Digital drive. Used an image along with WinMFS and all works good. I also happen to have a 500GB external USB drive. It happens to have a eSata port as well as a standard USB port. Could I plug this external drive (via its eSata connection) into my S3 and get some additional recording space? Or is some sort of special procedure required?

Now, I also happen to have a USB to eSata adapter cable. Could I maybe use this cable too to accomplish the same thing with any regular external USB drive? I also realize that ANY kind of external drive option means any new recordings are gonna be recorded across both drives so failure of one drive means loss of recordings no matter what.

The reason I ask is I thought I remember reading in the past how if you upgraded your internal drive, eSata expansion of any kind was no longer an option. Just wondering if that is still the case (or even true to begin with).