I think, I can confirm that it depends on the encoding of the other client. I did a bit of testing, and found out, that if the other side uses a UTF-8 enabled Miranda Build[1] everything works fine.
[1] http://www.madman2k.net/?module=comments&id=31 -- error with recieving german umlauts over ICQ protocol https://launchpad.net/malone/bugs/38065 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
