Backup file names with rman run by Grid Control (11g)

On UNIX systems, I have been able to control what the backup file names look like by using a combination of shell and rman variables when I allocate a channel. For example:

BASE_NAME= 'date+$1_%y%m%d%H%M%S' (where $1 is the database name)
...

Rman target ...
{
allocate channel ch1 type disk format '$BACKUP_DIR2/${BASE_NAME}_1_%U.rbk';
...

This gives me file name in the format <database name>_<date time>_<channel #>_<unique id>.rbk.

When I set up my backups with grid control, it uses the value that I enter in the disk backup location field (Backup Settings->device) to determine where to put the backup files, but the names are cryptic. Is there a way to specify the format?

Thanks,
Peter Schauss

--
http://www.freelists.org/webpage/oracle-l