How to add multiple namespaces in Soap Envelope

[monuindia2002]

Hi
I am writing a soap message manually by using XMlTextWriter, in which i want to write this line.
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
i am writing these lines to construct this envelope element
Private iSoapSchema As String = http://schemas.xmlsoap.org/soap/envelope/
iSoapEnvelope.AppendChild(iSoapEnvelope.CreateElement("soapenv", "Envelope", iSoapSchema))
with these 2 lines i am getting only this
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
how can i add more namespaces in this envelope element manually
Please help me,
it's very urgent.

regards
Mahesh