SafeDisc 2 is a bit weird indeed... Usually there's are three groups of writers: the ones that can copy SD2 without a problem, the ones that can copy SD2 but the copy will only work in the writer (and some other CD-ROMs like in your case), and the ones that simply cannot do it. A good list to check out to which your burner belongs is the CloneCD hardware requirements (check if correct EFM encoding is supported) and my own list.
Ps. the latest CloneCD version will sometimes make working back-ups with burners that aren't supposed (well they're supposed to make copies that work in the writer only) but this is an exception (but not a rare one for that matter).
For more info on SafeDisc 2 check here.