How to modify SOAP header or add namespace prefix to the elements using workflow

 Hi All,

We are trying to find ways to change SOAP-ENV:Envelope section of the SOAP messages created by Siebel when invoking external web-services ? Currently Siebel is creating below SOAP request I am using to test the integration.

<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">

   <SOAP-ENV:Header>

      <wsse:Security xmlns:wsse="http://schemas.xmlsoap.org/ws/2002/07/secext">

         <wsse:UsernameToken>

            <wsse:Username>****</wsse:Username>

            <wsse:Password>****</wsse:Password>

         </wsse:UsernameToken>

      </wsse:Security>

   </SOAP-ENV:Header>

   <SOAP-ENV:Body>

      <executeService xmlns="http://XMLTagNamespace">

         <serviceName>SERVICENAME</serviceName>

         <inputData>