Can't attach files containing scandic characters in name

We have a problem when trying to attach or access files with scandics in file names. We are running Confluence
Version: 1.4.1 Build:#212 Jun 02, 2005

Platform information:
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• Confluence is running on Debian platform 2.2.20-idepci
• mysql-standard-4.0.22-pc-linux-i686
• jakarta-tomcat-4.1.31

Usage scenario and problem description:
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First I tried to attach a file named "Ääkkösiä nimessä.txt" into my Confluence page named "Ääkköstesti ääkkösliitteille"
1) created in my local machine
/temp/Ääkkösiä nimessä.txt

2) tried to attach above file
=> browsed the file name to "Attach file" field, inserted also comment "ääkkösiä nimestä löytyy", pressed 'Attach File'

=> got error message box with:
"The following error(s) occurred:

• Ääkkösiä nimessä.txt does not exist."

Then I tried to access an attachment file (with scandics in name) that was attached before we upgraded to 1.4.1
3) tried to access an ääkkös-attachment attached before the Confluence upgrade => got error message bot with: "The page you were trying to reach does not exist. You may want to try a search, or browse the site to find the page you were looking for."

• KB machine language: LANG=en_IN (checked by env -command)
• Checked that Confluence encoding is set to UTF-8
• Client version:Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.8) Gecko/20050511 Firefox/1.0.4
• Client's language was: Western ISO-8859-1 (or -15), tried also with UTF-8 encoding with no change to the problem