action : unqualified action used in rio, e.g. "aanleveren_aangebodenOpleiding"
credentials : map with following keys: "keystore", "trust-store", "keystore-pass", "trust-store-pass", "private-key", "certificate"
rio-sexp : datastructure in hiccup-format representing the part of the API-call to RIO that will be wrapped in a "_request"
soap-action : qualified name used in SOAP-header, e.g. "http://duo.nl/contract/DUO_RIO_Beheren_OnderwijsOrganisatie_V4/aanleveren_opleidingsrelatie"
target : name of rio-entity, such as "aangebodenOpleiding", which is part of the "action".