Header and footer from Template not included after AppendDocument

Hi,
I am creating a document like this:

Document FinalDocument = new Document();
IList <string> sections = new List <string> ();
DocumentBuilder builder = new DocumentBuilder(FinalDocument);
Document frontPage = CreateFrontpage();
builder.Document.AppendDocument(frontPage, ImportFormatMode.KeepSourceFormatting);
// Save the finished document.
string dstFileName = "FinalDocument" + DateTime.Now.ToFileTime() + ".docx";
FinalDocument.Save(dataDir + dstFileName);
private static Document CreateFrontpage()
{
    string srcFileName = dataDir + "Frontpage.docx";
    IDictionary <string, object> attributes = AttributeHandler.GetAttributes(front);
    Document doc = new Document(srcFileName);
    DocumentBuilder builder = new DocumentBuilder(doc);
    FootnoteOptions footnoteOptions = builder..FootnoteOptions;
    // Execute the mail merge.
    doc.MailMerge.Execute(attributes.Keys.ToArray(), attributes.Values.ToArray());
    return doc;
}

Frontpage.docx contains a header and a footer, but this is not included in the FinalDocument.
Why do i enable the footer and header on the frontpage of a document?

Hi
Thanks for your request. Could you please attach your source documents, output and expected output documents? I will check the issue and provide you more information.
Best regards,