https://learn.microsoft.com/en-us/dotnet/api/microsoft.sqlserver.dts.tasks.webservicetask.webservicetask.savetoxml?view=sqlserver-2019
WebServiceTask.SaveToXML(XmlDocument, IDTSInfoEvents) Method...
This method is not callable by your application code. To save a package as .xml, use the SaveToXml(String, Package, IDTSEvents) method.
xmldocumentmethod