Update 2: Spoke with the techs at Sans Digital (the Raid unit), and it turns out that not all eSata chipsets function with all eSata devices (everything is too new, apparently), so I purchased a card from them directly, one they know is compatible. Suppose I should have done that from square one, but, hey, things are supposed to work together. We'll see what happens when the new card arrives!
JimmyD