Hi
I find this is a very great plugin for wordpress,
but all Chinese character would be displayed as diamonds in the pdf file ,maybe lack of the needed fonts ,really hope you can support chinese character , also I 'd love to do some translation work for you ,
I see the chinese version of your homepage http://zh.pdf24.org/ , like a machine translated,and most dose not make any sense ,like "100% Free | 100% Free of spyware" is "100%免费| 100%免费的间谍软件" in the zh page ,which means "a 100% free spyware", all the opposite , I thins it should be "100%免费| 100%无广告 无插件" and this kind of description used a lot in chinese software sites which means in english "free ware ,no ads no spyware"