InfoPath Dev

How can I write custom code that creates a new item in a Sharepoint form library? The only way I find out is to open an existing item via the object model and modify its nodes. But what can I do if no file exists?

This is my current approach (that uses an existing file to create a new one):

            SPFile spTemplate = webSite.Folders[libraryName].Files[0];

            // reads the blank file into an xml document
            MemoryStream inStream = new MemoryStream(spTemplate.OpenBinary());
            XmlTextReader reader = new XmlTextReader(inStream);
            XmlDocument xd = new XmlDocument();
            xd.Load(reader);
            reader.Close();
            inStream.Close();

            XPathNavigator xpn = xd.CreateNavigator();

            xpn.SelectNode(...).SetValue(newValue);

Ofcource you need to have some schema, wich describes your template file. You may use your form library template to get this xml file instead webSite.Folders[libraryName].Files[0]...

That means I have to extract the .xsn file and use the schema definition in this cab file? Is there any code snippet how this works?