Why does .NET XMLSerializer automatically change my namespace prefixes (alias)? - vb.net

Question

I am working on a web service that needs to return faults in a way that is defined by the standards of our type of business. This requires me to return a fault as this:
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Header>
<wsse:Security xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<Timestamp xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" />
</wsse:Security>
</soap:Header>
<soap:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<soap:Fault>
<faultcode>s:Server</faultcode>
<faultstring>Operator/operand type mismatch.</faultstring>
<faultactor>urn:dealernumberID:??????</faultactor>
<detail>
<ErrorType xmlns="http://www.starstandards.org/webservices/2009/transport">Backend Client Fault</ErrorType>
<ErrorDetail xmlns="http://www.starstandards.org/webservices/2009/transport">Backend client returned a fault</ErrorDetail>
</detail>
</soap:Fault>
</soap:Body>
</soap:Envelope>
I create the fault like this, but when the service sends it, it looks like this:
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Header>
<h:Security xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:h="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd">
<Timestamp xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" />
</h:Security>
</s:Header>
<s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<s:Fault>
<faultcode>s:Server</faultcode>
<faultstring>Operator/operand type mismatch.</faultstring>
<faultactor>urn:dealernumberID:??????</faultactor>
<detail>
<ErrorType xmlns="http://www.starstandards.org/webservices/2009/transport">Backend Client Fault</ErrorType>
<ErrorDetail xmlns="http://www.starstandards.org/webservices/2009/transport">Backend client returned a fault</ErrorDetail>
</detail>
</s:Fault>
</s:Body>
</s:Envelope>
Why does this happen? Is there a setting that I can change in .NET to keep it from doing this by default? I do understand that a namespace is a namespace regardless of the prefix, but like I said, the standard dictates we do it a certain way (most likely to accommodate third parties that are reading responses as strings?)
Thanks for any help!