Cannot search by Korean Character on Text Search Query!!!!!!

Now, we are concerning to use JIRA as main ITS in our company which is IDIS in Korea.

However, we cannot search with Korean character on Text Search Query!!
This is quite big problem for us who use Korean as official language.

I also tried to change 'indexing language' option on 'Internationalisation' of 'General Configuration', but nothing is improved.
Do I have to change 'Character Encoding' to solve this symptom? If yes, do I use external DB for JIRA to allow to search by Korean?

Now, this problem is blocking us to concerning to use JIRA. It's so urgent.
I think most of eastern companies have same trouble.

Please give us your quick answer~.