XFA form loses interactivity when filling XML data with IText

Question

I have an Adobe LiveCycle form which is dynamically composed. We need to load XML data into this form. I tried that with IText and it worked. But after filling the form it has lost its interactivity. How do I fill the form so that it still generates the fields when opened and executes the JavaScript behind it? For the filling I used the following code snippet (template Itext):

    public class FillXFA
{
    public static readonly String DEST = "dest/path";

    public static readonly String SRC = "src/path";
    public static readonly String XML = "xml/path";

    public static void Main(String[] args)
    {
        FileInfo file = new FileInfo(DEST);
        file.Directory.Create();

        new FillXFA().ManipulatePdf(DEST);
    }

    protected void ManipulatePdf(string dest)
    {
        PdfDocument pdfdoc = new PdfDocument(new PdfReader(SRC), new PdfWriter(dest));
        PdfAcroForm form = PdfAcroForm.GetAcroForm(pdfdoc, true);

        XfaForm xfa = form.GetXfaForm();

        // Method fills this object with XFA data under datasets/data.
        xfa.FillXfaForm(new FileStream(XML, FileMode.Open, FileAccess.Read));
        xfa.Write(pdfdoc);

        pdfdoc.Close();
    }
}