Problem with Unicode Hindi url in WordPress

Hi,

I have wordpress version 2.9.2 on IIS7 server hosting.
Wordpress installed on http://example.com/takneek/

My problem is if I use any unicode hindi character in wordpress url then wordpress completely ignores it. For example:

“http://example.com/takneek/2010/03/रिंगटोन-बनाएं” URL is treated like “http://example.com/takneek/2010/03/” and therefore shows archive list of March 2010.

“http://example.com/takneek/2010/03/रिंगटोन-बनाएंxyz” URL is treated like “http://example.com/takneek/2010/03/xyz” and therefore shows 404 page.

“http://example.com/takneek/2010/03/create-ringtone” works perfectly.

However my local installation on WAMP server works fine with unicode urls.

Please help. It is urgent.