Is it possible to insert Japanese characters into a table with NVARCHAR2 data type column on a datab

  Greetings,

Could someone please help me with a problem I am faced with. 

Is it possible to insert Japanese characters into a table with NVARCHAR2 data type column on a database with NLS_NCHAR_CHARACTERSET set to UTF8 and NLS_CHARACTERSET set to WE8ISO8859P15 using for example SQL*Plus or SQL Developer?

I have tried the following. 

1. Installed Japanese Language pack to my Windows 7 workstation.

2. Changed the NLS_LANG in registry to my environment variables with either JAPANESE_JAPAN.WE8MSWIN1252 or AMERICAN_AMERICA.UTF8. 

3. Also tried to alter the session with following commands.

ALTER SESSION SET NLS_LANGUAGE = 'JAPANESE';