In C# I can do the following:
var header = MessageHeader.CreateHeader("MyHeader", "http://mynamespace", "Header value");
OperationContext.Current.OutgoingMessageHeaders.Add(header);
That adds the following to the SOAP message:
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Header>
<MyHeader xmlns="http://mynamespace">Header value</MyHeader>
....
</s:Header>
...
How can I similarly add a custom outgoing SOAP message header when calling methods on a proxy generated by the New-WebServiceProxy PowerShell commandlet?
Edit: To clarify, I can make the same calls in PowerShell that I show in the C# above, but OperationContext.Current is always null. I get around that in C# by creating an OperationContextScope, but that requires the inner channel of the web service proxy, which PowerShell's proxy doesn't seem to provide.