You MUST set to "Keep Türkçe Characters in Non-URLS" just as ti is described in integration manual (there is about English but it is same - you just have internationalized vBSEO). Otherwise vBESO will remove each not Turkish character which for Japanese leaves nothing... That is why you have issue with Japanese or Arabic (and probably some other languages too).
If you still do not want to have Turkish characters in your URL you have to:
1. open /includes/config_vbseo.php
2. Find:
PHP Code:
// ****** CUSTOM CHARACTER REPLACEMENTS ******
// The following array enables you to select a replacement for characters other than the ones replaced
// by default.
$vbseo_custom_char_replacement = array();
3. Put there replacement pairs for Turkish characters.
I.e. for polish letters it looks like this:
PHP Code:
$vbseo_custom_char_replacement = array(
'ˇ' => 'A',
'¦' => 'S',
'¬' => 'Z',
'±' => 'a',
'¶' => 's',
'Ľ' => 'z',
'ą' => 'a',
'ę' => 'e',
'ć' => 'c',
'ż' => 'z',
'ś' => 's',
'ź' => 'z',
'ó' => 'o',
'ł' => 'l',
'ń' => 'n',
'Ą' => 'A',
'Ę' => 'E',
'Ć' => 'C',
'Ż' => 'Z',
'Ś' => 'S',
'Ź' => 'Z',
'Ó' => 'O',
'Ł' => 'L',
'Ń' => 'N'
);
I'm sure that if you search on vBSEO forum or ask there you will get appropriate replacements pairs for Turkish characters 
If you have any other questions about this issue - please just ask