I have a TM backup partitioned-volume as well as a Superduper clone partitioned-volume on a FW 800 drive (connected by a FW 800 cable).
I use DU to dismount the clone partition before turning TM On; as result, TM doesn't see the dismounted clone-partition. (I have also deleted the clone partition in the TM prefs - when the clone partition was mounted - so TM does not try using the clone partition.)
I am also careful to turn TM Off before activating Superduper to clone.
(Of course, I then must dismount the clone partition to then, re-activate TM.)
This "procedure" might seem a bit kludgy, but it's just several clicks for steps.
No problems.
