Post truncated after special characters

Not a new problem on WP forums, but I’m having problems figuring out where the root cause is.

I have problems saving posts that contain the double quotes and single curly quote marks wptexturize generates. I can live with this, it’s slightly annoying when doing copy/paste jobs but it’s not a dealbreaker.

My problem: this truncate bug also occurs for accented characters.

Example: If I write Vujač
Result: It will appear as Vuja

My database is using utf-general-ci for collation, and utf8 as the charset. Apache is using PHP5, not PHP4.

Inside wp-config.php, it shows this:
/** Database Charset to use in creating database tables. */
define(‘DB_CHARSET’, ‘utf8’);

/** The Database Collate type. Don’t change this if in doubt. */
define(‘DB_COLLATE’, ”);

I have tried changing the collate option to ‘utf-general-ci’ and ‘utf-unicode-ci’, both did not solve my problem. Is there some option I missed somewhere, or does the problem lie somewhere else (theme, plugin, Apache config)? Any help is greatly appreciated.

My site is currently under construction, but I can provide a test account via email for testing.