Display Messages in the dialog box (F11) on multiplayers

In solo games a text displayed with DisplayText... is also written in the dialog box.
But when it is a multiplayer game, is there a way to display a message in the box ?

I know i could use a multiboard instead, but that's a pretty ugly way ...

No. It's implemented in warcraft because in singleplayer there won't be text from other players (that would be freaky).

You can not save test in the box while in multiplayer. This happens because you have another box called "chat" which you can also consult to see the text.
You can, however, use the quest menu if you want, but I don't think that would be a nice idea...