I would not use the discovery probe. You can do all this via the RESTmessagev2 api. You can create a rest message record, use thw workflow to call message. In that record you can pick what mid server you want to use, in the record, it will give you the script to use. 

https://docs.servicenow.com/bundle/newyork-application-development/page/integrate/outbound-rest/task...