Not sure if people have translated this, but.
Since this image has traditional Chinese, I figured I’d translate it.
See you again when victory is obtained.
Your loyal son,
So it’s actually a letter from Lu Ten to Iroh. The grammar is very simple, almost like a telegram, so you can take it as “I’ll see you again when I obtain victory.” A lot of people think that “xai gien,” the last two characters of the second line means “goodbye,” but it literally just means “see you again,” and in this context it does not mean farewell.
Thanks for late night tearbending, Youko.