Can anyone tell me how to restart a failed CommVault v7 backup job?

I have a tape library connected to a FAS3070 via SCSI and have managed to write 3 Tb to tape when a network error between the filer and CommVault management agent killed the job.  CommVault has restarted the job from the begining again but the filer has shows the snaphot as (busy, backup, dump) and backup status as

ID     State     Type  Device   Start Date   Level  Path
--  -----------  ----  ------  ------------  -----  ---------------
0  RESTARTABLE  NDMP          Jul 01 15:05    0    /vol/dmfil01wsf/
1  ACTIVE       NDMP  ndmp    Jul 02 17:35    0    /vol/dmfil01wsf/

I know how to terminate the job on the filer but would like to continue from the point of failure if posible.

Thanks

Brendon