http://bugs.winehq.org/show_bug.cgi?id=13891
--- Comment #54 from Vincent Povirk madewokherd@gmail.com 2010-05-13 16:33:25 --- I've sent some patches: http://www.winehq.org/pipermail/wine-patches/2010-May/088370.html
The tests and WM_DDE_EXECUTE documentation lead me to believe that ddeml expects UNICODE data if both client and server are unicode and ANSI-OR-MAYBE-UNICODE data otherwise, and that it converts that on the server side based on whether DdeInitializeA or DdeInitializeW is called.
If any cases are still broken because of the odd usage of a CONVCONTEXT structure, they should be fixed on the client side where that structure is accessible. I have no reason to believe that structure has any meaning in the low level dde protocol, and therefore I don't believe it's possible for the server to retrieve the structure as the client has it.