Hi,

Out of the box, ob-ditaa does not work with non-ascii characters.

I looked into the problem in order to answer a user request on
StackOverflow (yes, there are org-mode questions posted there instead
of here!).

http://stackoverflow.com/questions/5758498/problem-with-ditaa-and-foreign-characters-in-org-mode

In order for ditaa to accept UTF-8 characters in the input file, it
must be called with the corresponding property setting:

   java -Dfile.encoding=UTF-8 -jar path/to/ditaa.jar ...

Attached is a dirty patch for hard-coding this property setting.

I don't know what the proper way of setting this property should be:

 - somehow setting it system-wide (any Java guru out there?).

 - or adding a customization to ob-ditaa.el for this property

 - or adding magic to ob-ditaa so that the same encoding of the buffer
   gets set to this Java property

I can help with the implementation if given some feedback on the above
options.

Regards,
.j.