Major Description
This is related to ODE-343, see for context.
The xsi:type attribute goes missing when you define a type attribute.
Example:
<soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:myns="myns">
<soapenv:Header/>
<soapenv:Body>
<myns:hello>
<myns:in xsi:type="myns:DustyMagicPixie" type="Why">
<myns:value>Test message</myns:value>
<myns:dust>fooo</myns:dust>
</myns:in>
</myns:hello>
</soapenv:Body>
</soapenv:Envelope>