Interestingly, the option you want looks like it is a volume attribute.
Take a look at "volume modify -sched-snap-name".
Quoting from the Commands_Manual_Page_Reference under the volume modify command:
[-sched-snap-name {create_time|ordinal}] - Naming Scheme for Automatic Snapshots
This option specifies the naming convention for automatic Snapshot copies. If set to create-time, automatic Snapshot copies are named using the format <schedule_name>.yyyy-mm-dd_hhmm. Example: "hourly.2010-04-01_0831". If set to ordinal, automatic Snapshot copies are named using the format <schedule_name>.<n>. Example: "hourly.3"