How can I check if a Virt Service received a certain REST call?

Dear,

I have to test if our service sends a REST call to an external service.

This REST call is the result of an assynchrone process, so I don't know when this will happen.

Our service doesn't need a response from the external service and I don't have access to this external service.

My idea is to virtualise this external service and check once in a while if it received this REST call and what the content was of this call.

I'm new with ServiceV so I want to know if this is possible and if yes how do I do this?

Thanks

Johan