I have tested under both Windows & Ubuntu Linux, it seems like we can do that.
I have tested with Chinese , Spanish , Japanese and Tamil.
RC2 binary (Windows) is built with non-Unicode support , you need to compile yourself a Unicode version.
However , recently, while I am doing testing in wxSmith , I found that TinyXML seems like cannot handle Unicode well , xrc export in wxSmith CANNOT save Double Byte character properly .