TF BCV target used as clone source

greetings all - my question involves TF mirror operations and snaps/clones using the symmir target as the source for those snaps/clones.

first off the details in the environment....
DMX-4 - 5772.85
SE - 6.4.3

I am setting up a new environment and I have a 2-way-mir STD - Raid-5 BCV establish that runs every night as a part of our nightly sync process for backups of oracle databases and applications. Every 3 months or so, there is a adhoc clone that runs using that same RAID-5 BCV as the source for the clone. In order for the clone to run (even though the std/bcv devices are split), I have to issue the symmir cancel command to remove the STD/BCV relationship, and the subsequent first establish that runs after that clone has been terminated MUST be a FULL copy. Now the difference between an incremental and full copy on these devices is almost 35 minutes which hinders an already tight backup window...Is there anything I can do to activate this clone without removing the std/bcv relationship.........I have a similar environment where I do the same thing with a snap instead of a clone, and it works fine......