I live in Durham, NC and just got the Samsung SMT-H3772 Set-top-box / DVR when I signed up with Time Warner. The internal HD has 500GB, which is pretty good size DVR HD, but I didn't want to worry about running out of space any time soon, so I bought a Western Digital My Book AV DVR Expander (1TB) external hard drive.
When I plugged it in via the eSata cable, nothing happened. Next I tried the USB port, still no dice. According to WD and Samsung, the set-top-box should automatically sense the external hard drive and add it to the total available space for recording shows.
Next, I went online to try to find out if anyone else was having the same problem with adding an external hard drive to the Samsung SMT-H3727 from Time Warner. Unfortunately, I didn't find any other posts on the subject online.
With no other recourse, I went online to use the Time Warner chat function to find out what the deal was. At first the support specialist told me they don't disable ports, but then later revised that to say they disable the USB and eSata port, but not the FireWire port.
Thus, the only way to successfully add an external hard drive to the Time Warner Samsung SMT-H3727 is to get a FireWire to USB or eSata adapter.
I haven't tried it out yet, but figured I'd share the info in case anyone else comes searching.