Add Elements in Existing XML File in C#.Net

Hi friends,
I create a XML file using C#.net. XML file structure is like this
<Test>
<Software>
<Code>Yes</Code>
</Software>
</Test>
I want to add a element when click a button.So i create a method in C#.net.
private static void InsertNode(string xmlFilePath,string xmlNode,string innerText)
{
try
{
XmlDocument xmlDoc = new XmlDocument();
xmlDoc.Load(xmlFilePath);
XmlNode root = xmlDoc.DocumentElement;
XmlElement xmlEle = xmlDoc.CreateElement(xmlNode);
xmlEle.InnerText = innerText;
root.InsertAfter(xmlEle, root.SelectSingleNode("/Software"));
xmlDoc.Save(xmlFilePath);
MessageBox.Show("Saved Successfully");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void button1_Click(object sender, EventArgs e)
{
InsertNode(xmlPath + "\\Default.xml", "Function", "true");
}

But it works fine . I got a output
<Test>
<Function>true</Function>
<Software>
<Code>Yes</Code>
</Software>
</Test>
but i want like this
<Test>

<Software>
<Code>Yes</Code>
<Function>true</Function>
</Software>
</Test>
So how can i achieve this ? Please help me.