Hi,
thx Madu for your post. I was always trying to update description or content, but enough is to update only articlexml.
Example:
articleEntity.SubjectId = new EntityReference(Subject.EntityLogicalName, caseEntity.SubjectId.Id);
articleEntity.Title = caseEntity.Title;
articleEntity.KbArticleTemplateId = new EntityReference(KbArticleTemplate.EntityLogicalName, articleTemplate.Id);
articleEntity.Description = caseEntity.Description;
articleEntity.ArticleXml = "<articledata><section id='0'><content><![CDATA[" + caseEntity.Description + "]]></content></section></articledata>";
Guid articleEntityGuid = service.Create(articleEntity);
Using this approach 'kb article data' is updated with any content you need -> in fact article template contains sections (e.g.: question, answer, additional comments,..) and those sections are fullfilled with articlexml. 'Section id' represents index of section. For update of more sections, see sample below (if you will try to update sections, which does not exist in template, entity will not crash ;)
articleEntity.ArticleXml = "<articledata><section id='0'><content><![CDATA[" + caseEntity.Description + "]]></content></section><section id='1'><content><![CDATA[" + caseEntity.Description + "]]></content></section></articledata>";
Stan