3.5.5 Mail merge creates document with fields instead of editable text

I have several templates that I use to create documents from a Base db. In OOo 3.3, printing a mail-merge creates editable documents that I can tweak if necessary. In LibreOffice, it creates documents filled with the fields that should have been replaced. The replacement text is in the field, but is not editable.

Please see pictures at https://picasaweb.google.com/112200146893522559516/MailMerge?authkey=Gv1sRgCInbnpW49KmULA

There are a lot of options and variants how to create a mail merge document. Could you add how you did proceed?