how tol oad test request which are signed(hash) every request and response

I'm trying to simulate the load of some product which basically communicates in SOAP XML format. The CDATA contains the actual JSON, which will be taken further for processing.

The requests contain, public key using which it can decode the incoming request to check that has not tampered and the same for outgoing as well.

Both of the send and receiver has private keys and pass public key while signing the requests/response.

What is the best way to simulate such request, example Client A sends Request to Server Server Respond(with some important data like certificates) Client The client now generated the ACK(which uses the certificate values to encode the response) to the Server

How to simulate such request for load testing, I'm using Jmeter and NEoload.

I can send the first request, get the response and work on the response to create the ACK response(it fails because it is generating the signature with a hash).

Does any tool support this kind of behaviour or what is the best way to simulate such a request?