using (WordprocessingDocument package = WordprocessingDocument.Create(fileName, WordprocessingDocumentType.Document))

{

    MainDocumentPart mainPart = package.AddMainDocumentPart();

    using (Stream stream = mainPart.GetStream())

    {

    }

}

wml2 inner = wml2.CreateDocument();

CT_Document ct_doc = inner.document.Append();

CT_Body ct_body = ct_doc.body.Append();

CT_P ct_paragraph = ct_body.p.Append();

CT_R ct_run = ct_paragraph.r2.Append();

CT_Text ct_text = ct_run.t.Append();

ct_text.Value = "Manipulations autour du format WordML";

UTF8Encoding encoding = new UTF8Encoding();

byte[] array = encoding.GetBytes(inner.Node.InnerXml);

//  Ecriture du fichier word/document.xml

stream.Write(array, 0, array.Length);

MainDocumentPart mainPart = package.AddMainDocumentPart();

MainDocumentPart mainPart = package.MainDocumentPart;