Proxy SOAP request, Headers not being forwarded

I have the proxy working with the exception of forwarding a SOAP request. A few headers are not being forwarded.

I am making my SOAP request via jquery.soap

$.soap({
    url: webServiceURL,
    type: 'POST',
    SOAPAction: 'GET_'+method,
    appendMethodToURL: false,
    data: soapEnvelopeHeader + soapBodyHead + params + soapBodyFooter + soapEnvelopeFooter,
    HTTPHeaders: {
      Authorization: 'Basic ' + btoa('username:password')
    },
    ...
});

The Authorization header and the SOAPAction headers are both being stripped.

I went through and logged the HeaderName as each header is being copied and they are getting stripped out before that point.

Any suggestions.

Start by tracing the proxy's header-copying path, using the reported logging point to determine where Authorization and SOAPAction are removed. The issue is done when both headers from the jquery.soap request reach the proxied SOAP request; no source file or test is named in the report.