Oracle Database Discussions

Friends,

OS: RHEL AS 3.0
DB: 9iR2

i checked the nls date parameter in sqlplus as sysdba. it shows the below output
sql> show parameter nls_date_format
DD-MON-YYYY

i checked the date format in rman by
rman>list backup;
all the date part of this output is showing the date format as dd-mon-yy

how come the rman is not taking the parameter's nls_date_format?
when i execute the below command in rman..

rman>RUN
{
SET UNTIL TIME 'Oct 27 2007 09:00:00';
RESTORE DATABASE;
RECOVER DATABASE;
}

it throws ORA-01858 error.

what should i do?
can i....

export NLS_DATE_FORMAT="DD-MM-YYYY HH24:Mi:SS"
then run

rman>RUN
{
SET UNTIL TIME '27-Oct-2007 09:00:00';
RESTORE DATABASE;
RECOVER DATABASE;
}


thanks