I would like to enquire how to make a direct input of a non-western character when editing a table to insert a new record in pl/sql.

For example, i have tried using IME 2000 (or copy any non-western text from websites) to key in chinese or japanese character as a record into a table ... but it shows up as ?.
The pl/sql is using NLS_LANG with appropriate character set as well as appropriate fonts set for the language used to key in the character.

Hope someone can help me on this.

Many thanks ....