Calling fnd_request.submit_request as REST API and getting on the submitted concurrent program.

Hi-

We're on Oracle EBS R12.2.10 and enabled the Integrated SOA Gateway for REST API Only. We were able to deploy the fnd_request.submit_request PL/SQL Package and assign appropriate grants. We were successful in calling the REST API from our REST Client (returning the Concurrent Request ID) but the actual concurrent program is failing probably due to the parameter list. The custom concurrent program takes only one parameter (Defined in the Concurrent Program) so we're sending this JSON payload:

{

  "SUBMIT_REQUEST_Input": {

    "@xmlns": "http://xxxx.com/apps/fnd/rest/Concurrent_Request/submit_request/",

    "RESTHeader": {

      "@xmlns": "http://xxxx.com/apps/fnd/rest/Concurrent_Request/header/"