Shoutbox

This doesnt work for the chat history showing up in the convo...

I don't know how it could be done some other way...
There isn't a way to send text to the local chatwindow only (as far as I know)

So it can't be done, OR your contact will see the history (quite annoying... when you open a window, he will receive a flood of text, not really an option) OR someone must find a way to send text localy...