Thanks for reply,
i can apply to myself the RTFM , when i take a look at log, i can see this entry:
<messages>
<timestamp>2013-04-04T14:28:10.161+02:00</timestamp><level>ERROR</level>
<thread>backup0 4ee709bc80c75fa7a36e9f34d3f5ca4b</thread>
<location>com.netapp.common.flow.TaskInstanceTemplate</location>
<msgKeyClass>com.netapp.common.MsgKey</msgKeyClass>
<msgKeyValue>FLOW_OPERATION_TASK_FAILURE</msgKeyValue>
<parameters><parameter>NaSnapshotCreateActionWrapper</parameter><parameter>Failed to rename snapshot smvi_Varis_novmsnap_20130404142605 to smvi_Varis_novmsnap_recent on volume 10.8.8.6:/vol/VOL_PROD_SR
</parameter>
</parameters>
<message>FLOW-11019: Failure in NaSnapshotCreateActionWrapper: Failed to rename snapshot smvi_Varis_novmsnap_20130404142605 to smvi_Varis_novmsnap_recent on volume 10.8.8.6:/vol/VOL_PROD_SR
</message>
</messages>
searching on forum can find the next KB:
https://kb.netapp.com/support/index?page=content&id=2014553
it seems that behavior is a bug of 4.0 version, i'll to rename the snapshot and install the newest version of VSC,
thanks,
best regards