Updating Content-Type to change soap action for SOAP 1.2 request is not working

Hi All, I am trying to change the SOAP action of a SOAP 1.2 version request in the “Request Processing” policy by updating the “Content-Type” in the PROTOCOL_HEADERS. But still, the request fails in the API GW showing

But I have in fact updated the virtualServiceBinder with the physical endpoint binder using “pub.apigateway.ctxvar:setContextVariable”.

I am doing the same thing for SOAP 1.1 version requests too by updating the “SOAPAction” in the PROTOCOL_HEADERS which works fine and perfectly. Issue is only with SOAP 1.2 requests.

Any ideas?