I purchased a Seagate External Sata Drive several years ago. It came with a Sata Interface Card from Promise. It works just fine but it does not work with Applications that rely on an "External" Hard Drive for Backup and Restore functions. From what I can determine, the Drive I purchased is "physically" external from my System but due to the Sata Interface Card appears as an additional Internal Sata Drive which cannot be used by the Backup and Restore Applications. They want a "real" external Drive as my USB Drives work just fine with the B&R Applications.
IS THERE A REAL / ANY DIFFERENCE IN SATA AND ESATA ADAPTER CARDS?
eSATA specifications made mandatory certain features like Hot Swap capability that are essential for a drive device that may be connected and disconnected while the system is running, whereas plain SATA did not require those features. Likewise, eSATA changed to higher signal voltages to allow data cables to be twice as long. Now, many manufacturers of plain SATA and SATA II controllers included some or all of these mandatory eSATA features even though they are not required in plain SATA controllers. For that reason, some people with eSATA external devices have had success with simple adapter plates that only convert a SATA port connector to a eSATA connector. They are depending on eSATA features built into the mobo plain SATA port. Some others use those adapters and simply never try to use the extra eSATA features, whether they are present or missing. The trouble is, most times you cannot tell whether a SATA controller has mandatory eSATA upgraded features built it.
In your case with a PCI-slot mounted SATA controller card, you'd have to go to its manufacturer's website to see if it can perform as a true eSATA controller. However, that point is moot. The card has some kind of port connector on it and you're not going to change that. From your description it sounds as if the port is plain SATA, not eSATA, and the external drive unit also has a SATA connector on it.
I am intrigued that your Backup and Restore applications refuse to make backup data sets to a device it determines is not external. Is there no way to bypass that restriction?