Nup, you do to_date and it converts it back to 2 YY, 2 digit year.

SQLWKS> select to_char(sysdate, 'DD-MON-YYYY') from dual;
TO_CHAR(SYS
-----------
22-FEB-2001
1 row selected.

SQLWKS> select to_date(to_char(sysdate, 'DD-MON-YYYY')) from dual;
TO_DATE(TO_CHAR(SYSD
--------------------
22-FEB-01
1 row selected.

I have no problem in using a variable to hold the value.
I think setting NLS_date format is the only option left.