encoding in XmlTextWriter ???

Question

Hi
I am using XmlTextWriter to create an xml document. 
Dim writer As New XmlTextWriter ("C:\test.xml", Encoding.UTF8)
The xml file has the following header...
<?xml version="1.0" encoding="utf-8"?>
Can someone show me please how to get the the encoding utf in capital letters...encoding="UTF-8"
Regards
Shaun