Saving stronged typed dataSet produces invalid XML document

[Bill]

I have a strong typed dataset which I load using the following code.

try
{
XmlTextReader xmlTR = new XmlTextReader("XIF-v1.0.xsd");
dsMyDataSet.ReadXmlSchema(xmlTR);
if (p_FileName != string.Empty)
{
_FileName = p_FileName;
dsMyDataSet.LoadData();
}
}
Catch (Exception e) {...}

When I am saving the dataset by either:

a) Using the dsMyDataSet.GetXml(); and saving to a file through an
XMLDocument or
b) using the dsMyDataset.WriteXml(); method to a file

I noticed a couple of things that causes an invalid XML document

First some of the elements are not in the same order which causes the
Xml document to, and second an extra tag is added <NewDataSet>

Any suggestions as to why this occurs and how to prevent would be
greatly appreciated.

Thanks

Bill