AjaxUpdateContainer fails to recognize utf-8 encoding ... because it sets the content-type to "text/plain" ...
I've fixed this in my own code (which is bad) and would like you guys to do something so that I can get rid of my hack and still enjoy the benefits of Ajax.framework ...
In handleRequest() ... about line ~ 145 ...
WOResponse response = AjaxUtils.createResponse\(request, context\);
// I added this line to get my umlauts back ...
response.setHeader("text/html; charset=utf-8", "content-type");
// end of my hack to get umlauts back
AjaxUtils.setPageReplacementCacheKey\(context, id\);