Seems to work with simplified Chinese if you put quotes around the string. Sort of a pain but at least you can get it out there. Possibly also just putting a space now and then would do it.
Looks like your test message was not big enough to trigger the string truncator. The character encoding you used allows for more characters per byte (hence the longer appearance relative to my test strings). If a longer message is made (in any encoding) it will be cut-off...