I have same problem as you. I use zh_HK-utf8.sql to make charts of account.
And also installed the language using Code 'zh_TW' and Encoding 'utf-8'.
All interface is working prefectly with chinese character but only account in combo box is shown as question marks.
Then I go to check my database and make sure it was encoded by 'utf8_unicode_ci'. I am sure that I can see correct chinese characters in phpMyAdmin.
I guess FA didn't encode and decode with correct CODE string 'zh_TW'.
I also found an insteresting thing is that to setup Encoding 'utf8' is differ with 'utf-8'. Even both can make whole interface work without probelm.
But if use 'utf8' , the title of the window is unknown characters, otherwise,use 'utf-8', the title is ok. So, I guess FA support 'utf8' and 'utf-8', but the Apache only support 'utf-8'.
I found my browser send 'zh-tw' to Apache (using phpinfo.php), so i changed FA CODE to 'zh-tw', but it still no work.
But if I enter the data of account from FA interface, I can read as what I entered, means that I can see correct chinese words. However I can not read it from phpMyAdmin, it is unknown words.