[Zope] UTF-8 conversion

Hi, We are running zope with ISO-8859-1 as the encoding for HTTP responses. In term of Zope objects, all the properties are lines, string, etc (not ulines, ustring, etc). Now, we have been asked to support Japanese (with UTF-8). So my question is: what should I need to change (in configuration) and do I need to migrate any ZODB data? Thanks. Pascal