Oracle sqlldr convert date field with different NLS_DATE_FORMAT
TO_DATE functions accepts the NLS language as an optional parameter .. have you tried pulling it in via SQL*Loader as a CHAR, then do a TO_DATE conversion on it inline?

so your SQL*loader syntax might look like:

  ...
    my_date     CHAR  "TO_DATE(:my_date, 'dd-MON-RR', 'NLS_DATE_LANGUAGE=American')"
  ...


See if that works any better ??