Loadrunner with Protobuf

Hi,

I am using LR12.0 to script a destop application using web+webservices protocols. Application had using protobuf for serialization and comapcting the XML. There are lot of proto tags in soap requests. I need to correlate the token within ptotobuf. Protobuf itself appears some latin.

I tried using DEF Binary to XML but data conversion is not happening in replay.

Can somebody help to resolve the following correation.

soap_request("StepName=CheckCredentials", 
        "URL=http://10.135.0.22/wcfstorm/wcfSecurity.svc", 
        "SOAPEnvelope="
            "<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\">"
                "<s:Body>"
                    "<CheckCredentials xmlns=\"http://tempuri.org/\">"
                        "<proto>CgA=</proto>"
                        "<proto></proto>"

<proto>wnZlCAASF1dJTkRPV1MhQUQtT05FXFJBSkVFVlNIGiFDTjohQkdFR0hNRD5XS1gxWTAuS01ELk9TRFJFQC1ES0wiA0NBRCoAMAE4AkgAUgYtMzI3NjhaEBSmMyJals1O9xOSrUgS69sKEBSmMyJals1O9xOSrUgS69s=</proto>"             
                    "</CheckCredentials>"
                "</s:Body>"
            "</s:Envelope>", 
        "Snapshot=t5.inf", 
        "ResponseParam=response", 
        LAST);

i need to correlate value  : <proto>wnZlCAASF1dJTkRPV1MhQUQtT05FXFJBSkVFVlNIGiFDTjohQkdFR0hNRD5XS1gxWTAuS01ELk9TRFJFQC1ES0wiA0NBRCoAMAE4AkgAUgYtMzI3NjhaEBSmMyJals1O9xOSrUgS69sKEBSmMyJals1O9xOSrUgS69s=</proto>

In this value only uS01ELk9TRFJFQC1ES0 this is changing everytime i script.